diff --git a/src/application/config/constants.php b/src/application/config/constants.php
index 994944c4..deefe73e 100644
--- a/src/application/config/constants.php
+++ b/src/application/config/constants.php
@@ -70,5 +70,7 @@ define('PAGE_SERVICES', 'services');
 define('PAGE_USERS', 'users');
 define('PAGE_SYSTEM_SETTINGS', 'system_settings');
 define('PAGE_USER_SETTINGS', 'user_settings');
+
+define('MIN_PASSWORD_LENGTH', 7);
 /* End of file constants.php */
 /* Location: ./application/config/constants.php */
\ No newline at end of file
diff --git a/src/application/controllers/backend.php b/src/application/controllers/backend.php
index e12587af..20a38410 100644
--- a/src/application/controllers/backend.php
+++ b/src/application/controllers/backend.php
@@ -143,17 +143,12 @@ class Backend extends CI_Controller {
         $this->load->model('settings_model');
         $this->load->model('user_model');
         
-        $this->load->library('session');
-        
-        // @task Apply data for testing this page (this must be done during the login process).
-        $this->session->set_userdata('user_id', 18);
-        $this->session->set_userdata('user_slug', DB_SLUG_ADMIN);
-        
+        $this->load->library('session');        
         $user_id = $this->session->userdata('user_id'); 
         
         $view['base_url'] = $this->config->item('base_url');
         $view['company_name'] = $this->settings_model->get_setting('company_name');
-        $view['user_slug'] = $this->session->userdata('user_slug');
+        $view['role_slug'] = $this->session->userdata('role_slug');
         $view['system_settings'] = $this->settings_model->get_settings();
         $view['user_settings'] = $this->user_model->get_settings($user_id);
         
diff --git a/src/application/controllers/backend_api.php b/src/application/controllers/backend_api.php
index b864c18d..9c7a555f 100644
--- a/src/application/controllers/backend_api.php
+++ b/src/application/controllers/backend_api.php
@@ -703,6 +703,13 @@ class Backend_api extends CI_Controller {
         try {
             $this->load->model('providers_model');
             $provider = json_decode($_POST['provider'], true);
+            
+            if (!isset($provider['working_plan'])) {
+                $this->load->model('settings_model');
+                $provider['settings']['working_plan'] = $this->settings_model
+                        ->get_setting('company_working_plan');
+            }
+            
             $this->providers_model->add($provider);
             echo json_encode(AJAX_SUCCESS);
         } catch(Exception $exc) {
@@ -822,6 +829,26 @@ class Backend_api extends CI_Controller {
             ));
         }
     }
+    
+    /**
+     * [AJAX] This method checks whether the username already exists in the database. 
+     * 
+     * @param string $_POST['username'] Record's username to validate.
+     * @param bool $_POST['record_exists'] Whether the record already exists in database.
+     */
+    public function ajax_validate_username() {
+        try {
+            // We will use the function in the admins_model because it is sufficient for 
+            // the rest user types for now (providers, secretaries).
+            $this->load->model('admins_model');
+            $is_valid = $this->admins_model->validate_username($_POST['username'], $_POST['record_exists']);
+            echo json_encode($is_valid);
+        } catch(Exception $exc) {
+            echo json_encode(array(
+                'exceptions' => array(exceptionToJavaScript($exc))
+            ));
+        }
+    }
 }
 
 /* End of file backend_api.php */
diff --git a/src/application/controllers/user.php b/src/application/controllers/user.php
index c3bb6a05..4966930f 100644
--- a/src/application/controllers/user.php
+++ b/src/application/controllers/user.php
@@ -13,11 +13,24 @@ class User extends CI_Controller {
     public function login() {
         $view['base_url'] = $this->config->item('base_url');
         $view['dest_url'] = $this->session->userdata('dest_url');
+        
+        if (!$view['dest_url']) {
+            $view['dest_url'] = $view['base_url'] . 'backend';
+        }
+        
         $this->load->view('user/login', $view);
     }
     
     public function logout() {
+        $this->session->unset_userdata('user_id');
+        $this->session->unset_userdata('user_email');
+        $this->session->unset_userdata('role_slug');
+        $this->session->unset_userdata('username');
+        $this->session->unset_userdata('dest_url');
         
+        $view['base_url'] = $this->config->item('base_url');
+        
+        $this->load->view('user/logout', $view);
     }
     
     public function forgot_password() {
@@ -37,17 +50,14 @@ class User extends CI_Controller {
                 throw new Exception('Invalid credentials given!');
             }
             
-            $this->load->helper('general');
             $this->load->model('user_model');
-            
-            $hash_password = $this->hash_password($_POST['password']);
-            $user_data = $this->user_model->check_login($_POST['username'], $hash_password);
+            $user_data = $this->user_model->check_login($_POST['username'], $_POST['password']);
             
             if ($user_data) {
                 $this->session->set_userdata($user_data); // Save data on user's session.
                 echo json_encode(AJAX_SUCCESS);
             } else {
-                echo json_encode(AJAX_SUCCESS);
+                echo json_encode(AJAX_FAILURE);
             }
             
         } catch(Exception $exc) {
diff --git a/src/application/helpers/general_helper.php b/src/application/helpers/general_helper.php
index 8f31c5a0..871c0cf6 100644
--- a/src/application/helpers/general_helper.php
+++ b/src/application/helpers/general_helper.php
@@ -29,13 +29,38 @@ function date3339($timestamp=0) {
  * Generate a hash of password string.
  * 
  * For user security, all system passwords are stored in hash string into the database. Use
- * this method to produce the hash.
+ * this method to produce the hashed password. 
  * 
+ * @param string $salt Salt value for current user. This value is stored on the database and 
+ * is used when generating the password hash.
  * @param string $password Given string password.
  * @return string Returns the hash string of the given password.
  */
-function hash_password($password) {
-    return md5($password); // @task include salt and hash more times.
+function hash_password($salt, $password) {
+    $salt = strtoupper($salt);
+    $password = strtoupper($password);
+    $half = (int)(strlen($salt) / 2);
+    $hash = hash('sha256', substr($salt, 0, $half ) . $password . substr($salt, $half));
+    
+    for ($i = 0; $i < 100000; $i++) {
+        $hash = hash('sha256', $hash);
+    } 
+    
+    return $hash; // @task include salt and hash more times.
+}
+
+/**
+ * Generate a new password salt.
+ * 
+ * This method will not check if the salt is unique in database. This must be done 
+ * from the calling procedure.
+ * 
+ * @return string Returns a salt string.
+ */
+function generate_salt() {
+    $max_length = 100;
+    $salt = hash('sha256', (uniqid(rand(), true)));
+    return substr($salt, 0, $max_length);
 }
 
 /* End of file general_helper.php */
diff --git a/src/application/models/admins_model.php b/src/application/models/admins_model.php
index 07f3f22c..38149563 100644
--- a/src/application/models/admins_model.php
+++ b/src/application/models/admins_model.php
@@ -85,6 +85,8 @@ class Admins_Model extends CI_Model {
      * @throws Exception When the insert operation fails.
      */
     public function insert($admin) {
+        $this->load->helper('general');
+        
         $admin['id_roles'] = $this->get_admin_role_id();
         $settings = $admin['settings'];
         unset($admin['settings']);
@@ -97,6 +99,8 @@ class Admins_Model extends CI_Model {
         
         $admin['id'] = intval($this->db->insert_id());
         $settings['id_users'] = $admin['id'];
+        $settings['salt'] = generate_salt();
+        $settings['password'] = hash_password($settings['salt'], $settings['password']);
         
         // Insert admin settings. 
         if (!$this->db->insert('ea_user_settings', $settings)) {
@@ -117,10 +121,17 @@ class Admins_Model extends CI_Model {
      * @throws Exception When the update operation fails.
      */
     public function update($admin) {
+        $this->load->helper('general');
+        
         $settings = $admin['settings'];
         unset($admin['settings']);
         $settings['id_users'] = $admin['id'];
         
+        if (isset($settings['password'])) {
+            $salt = $this->db->get_where('ea_user_settings', array('id_users' => $admin['id']))->row()->salt;
+            $settings['password'] = hash_password($salt, $settings['password']);
+        }
+        
         $this->db->where('id', $admin['id']);
         if (!$this->db->update('ea_users', $admin)) {
             throw new Exception('Could not update admin record.');
@@ -193,6 +204,24 @@ class Admins_Model extends CI_Model {
                 throw new Exception('Invalid email address provided : ' . $admin['email']);
             }
             
+            // Validate admin username 
+            if (isset($admin['settings']['username'])) {
+                $num_rows = $this->db->get_where('ea_user_settings', 
+                        array('username' => $admin['settings']['username']))->num_rows();
+                if ($num_rows > 0) {
+                    throw new Exception('Username already exists, please select another '
+                            . 'and try again (username: ' . $admin['settings']['username'] . ')');
+                }
+            }
+            
+            // Validate admin password
+            if (isset($admin['settings']['password'])) {
+                if (strlen($admin['settings']['password']) < MIN_PASSWORD_LENGTH) {
+                    throw new Exception('The user password must be at least ' 
+                            . MIN_PASSWORD_LENGTH . ' characters long.');
+                }
+            }
+            
             return TRUE;
         } catch (Exception $exc) {
             return FALSE;
@@ -328,6 +357,22 @@ class Admins_Model extends CI_Model {
     public function get_admin_role_id() {
         return intval($this->db->get_where('ea_roles', array('slug' => DB_SLUG_ADMIN))->row()->id);
     }
+    
+    /**
+     * Validate Records Username 
+     * 
+     * @param string $username The provider records username.
+     * @param bool $record_exists Whether the record exists or not.
+     * @return bool Returns the validation result.
+     */
+    public function validate_username($username, $record_exists) {
+        $num_rows = $this->db->get_where('ea_user_settings', array('username' => $username))->num_rows();
+        if ($num_rows == 0 && $record_exists == FALSE || $num_rows == 1 && $record_exists == TRUE) {
+            return true;
+        } else {
+            return false;
+        }
+    }
 }
 
 /* End of file admins_model.php */
diff --git a/src/application/models/providers_model.php b/src/application/models/providers_model.php
index 6ef9d0af..d84513a9 100644
--- a/src/application/models/providers_model.php
+++ b/src/application/models/providers_model.php
@@ -98,6 +98,8 @@ class Providers_Model extends CI_Model {
      * @throws Exception When the insert operation fails.
      */
     public function insert($provider) {
+        $this->load->helper('general');
+        
         // Get provider role id. 
         $provider['id_roles'] = $this->get_providers_role_id();
         
@@ -112,6 +114,9 @@ class Providers_Model extends CI_Model {
             throw new Exception('Could not insert provider into the database');
         }
         
+        $settings['salt'] = generate_salt();
+        $settings['password'] = hash_password($settings['salt'], $settings['password']);
+        
         $provider['id'] = $this->db->insert_id();
         $this->save_settings($settings, $provider['id']);
         $this->save_services($services, $provider['id']);
@@ -128,12 +133,19 @@ class Providers_Model extends CI_Model {
      * @throws Exception When the update operation fails.
      */
     public function update($provider) {
+        $this->load->helper('general');
+        
         // Store service and settings (must not be present on the $provider array).
         $services = $provider['services'];
         unset($provider['services']);
         $settings = $provider['settings'];
         unset($provider['settings']);
         
+        if (isset($settings['password'])) {
+            $salt = $this->db->get_where('ea_user_settings', array('id_users' => $provider['id']))->row()->salt;
+            $settings['password'] = hash_password($salt, $settings['password']);
+        }
+        
         // Update provider record.
         $this->db->where('id', $provider['id']);
         if (!$this->db->update('ea_users', $provider)) {
@@ -224,6 +236,24 @@ class Providers_Model extends CI_Model {
                 throw new Exception('Invalid provider settings given: ' . print_r($provider, TRUE));
             }
             
+            // Validate admin username 
+            if (isset($provider['settings']['username'])) {
+                $num_rows = $this->db->get_where('ea_user_settings', 
+                        array('username' => $provider['settings']['username']))->num_rows();
+                if ($num_rows > 0) {
+                    throw new Exception('Username already exists, please select another '
+                            . 'and try again (username: ' . $provider['settings']['username'] . ')');
+                }
+            }
+            
+            // Validate admin password
+            if (isset($provider['settings']['password'])) {
+                if (strlen($provider['settings']['password']) < MIN_PASSWORD_LENGTH) {
+                    throw new Exception('The user password must be at least ' 
+                            . MIN_PASSWORD_LENGTH . ' characters long.');
+                }
+            }
+            
             return TRUE;
         } catch (Exception $exc) {
             return FALSE;
diff --git a/src/application/models/secretaries_model.php b/src/application/models/secretaries_model.php
index 492db372..97a7a808 100644
--- a/src/application/models/secretaries_model.php
+++ b/src/application/models/secretaries_model.php
@@ -86,6 +86,8 @@ class Secretaries_Model extends CI_Model {
      * @throws Exception When the insert operation fails.
      */
     public function insert($secretary) {
+        $this->load->helper('general');
+        
         $providers = $secretary['providers'];
         unset($secretary['providers']);
         $settings = $secretary['settings'];
@@ -98,6 +100,8 @@ class Secretaries_Model extends CI_Model {
         }
         
         $secretary['id'] = intval($this->db->insert_id());
+        $settings['salt'] = generate_salt();
+        $settings['password'] = hash_password($settings['salt'], $settings['password']);
         
         $this->save_providers($providers, $secretary['id']);
         $this->save_settings($settings, $secretary['id']);
@@ -113,11 +117,18 @@ class Secretaries_Model extends CI_Model {
      * @throws Exception When the update operation fails.
      */
     public function update($secretary) {
+        $this->load->helper('general');
+        
         $providers = $secretary['providers'];
         unset($secretary['providers']);
         $settings = $secretary['settings'];
         unset($secretary['settings']); 
         
+        if (isset($settings['password'])) {
+            $salt = $this->db->get_where('ea_user_settings', array('id_users' => $secretary['id']))->row()->salt;
+            $settings['password'] = hash_password($salt, $settings['password']);
+        }
+        
         $this->db->where('id', $secretary['id']);
         if (!$this->db->update('ea_users', $secretary)){
             throw new Exception('Could not update secretary record.');
@@ -193,6 +204,24 @@ class Secretaries_Model extends CI_Model {
                 throw new Exception('Invalid email address provided : ' . $secretary['email']);
             }
             
+            // Validate admin username 
+            if (isset($secretary['settings']['username'])) {
+                $num_rows = $this->db->get_where('ea_user_settings', 
+                        array('username' => $secretary['settings']['username']))->num_rows();
+                if ($num_rows > 0) {
+                    throw new Exception('Username already exists, please select another '
+                            . 'and try again (username: ' . $secretary['settings']['username'] . ')');
+                }
+            }
+            
+            // Validate admin password
+            if (isset($secretary['settings']['password'])) {
+                if (strlen($secretary['settings']['password']) < MIN_PASSWORD_LENGTH) {
+                    throw new Exception('The user password must be at least ' 
+                            . MIN_PASSWORD_LENGTH . ' characters long.');
+                }
+            }
+            
             return TRUE;
         } catch (Exception $exc) {
             return FALSE;
diff --git a/src/application/models/user_model.php b/src/application/models/user_model.php
index 0fb003e8..53a2173e 100644
--- a/src/application/models/user_model.php
+++ b/src/application/models/user_model.php
@@ -35,6 +35,13 @@ class User_Model extends CI_Model {
         $user_settings['id_users'] = $user['id'];
         unset($user['settings']);
         
+        // Prepare user password (hash).
+        if (isset($user_settings['password'])) {
+            $this->load->helper('general');
+            $salt = $this->db->get_where('ea_user_settings', array('id_users' => $user['id']))->row()->salt;
+            $user_settings['password'] = hash_password($salt, $user_settings['password']);
+        }
+        
         if (!$this->db->update('ea_users', $user, array('id' => $user['id']))) {
             return FALSE;
         }
@@ -45,6 +52,43 @@ class User_Model extends CI_Model {
         
         return TRUE;
     }
+    
+    /**
+     * Retrieve user's salt from database.
+     * 
+     * @param string $username This will be used to find the user record.
+     * @return string Returns the salt db value.
+     */
+    public function get_salt($username) {
+        $user =  $this->db->get_where('ea_user_settings', array('username' => $username))->row_array();
+        return ($user) ? $user['salt'] : '';
+    }
+    
+    /**
+     * Performs the check of the given user credentials. 
+     * 
+     * @param string $username Given user's name. 
+     * @param type $password Given user's password (not hashed yet).
+     * @return array|null Returns the session data of the logged in user or null on 
+     * failure.
+     */
+    public function check_login($username, $password) {
+        $this->load->helper('general');
+        $salt = $this->user_model->get_salt($username);
+        $password = hash_password($salt, $password);
+        
+        $user_data = $this->db
+                ->select('ea_users.id AS user_id, ea_users.email AS user_email, '
+                        . 'ea_roles.slug AS role_slug, ea_user_settings.username')
+                ->from('ea_users')
+                ->join('ea_roles', 'ea_roles.id = ea_users.id_roles', 'innder')
+                ->join('ea_user_settings', 'ea_user_settings.id_users = ea_users.id')
+                ->where('ea_user_settings.username', $username)
+                ->where('ea_user_settings.password', $password)
+                ->get()->row_array();
+        
+        return ($user_data) ? $user_data : NULL;
+    }
 }
 
 /* End of file user_model.php */
diff --git a/src/application/views/appointments/book_success.php b/src/application/views/appointments/book_success.php
index 5320ea81..3ce128bb 100644
--- a/src/application/views/appointments/book_success.php
+++ b/src/application/views/appointments/book_success.php
@@ -149,7 +149,7 @@
                                             'Your appointment has successfully been added to ' +
                                             'your Google Calendar account. <br>' + 
                                             '<a href="' + response.htmlLink + '">' + 
-                                                'Click here to view your appoinmtent on Google ' +
+                                                'Click here to view your appointment on Google ' +
                                                 'Calendar.' +
                                             '</a>' + 
                                         '</p>' +
diff --git a/src/application/views/backend/header.php b/src/application/views/backend/header.php
index 42324473..634f70bf 100644
--- a/src/application/views/backend/header.php
+++ b/src/application/views/backend/header.php
@@ -103,7 +103,7 @@
         
         <?php // LOGOUT MENU ITEM 
               // ------------------------------------------------------ ?>
-        <a href="<?php echo $base_url; ?>backend/logout" class="menu-item">
+        <a href="<?php echo $base_url; ?>user/logout" class="menu-item">
             Logout
         </a>
         
diff --git a/src/application/views/backend/settings.php b/src/application/views/backend/settings.php
index 7487582b..d0d50330 100644
--- a/src/application/views/backend/settings.php
+++ b/src/application/views/backend/settings.php
@@ -8,7 +8,7 @@
 <script type="text/javascript">    
     var GlobalVariables = {
         'baseUrl': <?php echo '"' . $base_url . '"'; ?>,
-        'userSlug': <?php echo '"' . $user_slug . '"'; ?>,
+        'userSlug': <?php echo '"' . $role_slug . '"'; ?>,
         'settings': {
             'system': <?php echo json_encode($system_settings); ?>,
             'user': <?php echo json_encode($user_settings); ?>
diff --git a/src/application/views/user/login.php b/src/application/views/user/login.php
index 36febafa..7d185383 100644
--- a/src/application/views/user/login.php
+++ b/src/application/views/user/login.php
@@ -60,11 +60,13 @@
         }
     </style>
     
-    <script>
+    <script type="text/javascript">
         $(document).ready(function() {
             var GlobalVariables = {
                 'baseUrl': <?php echo '"' . $base_url . '"'; ?>,
-                'destUrl': <?php echo '"' . $dest_url . '"'; ?>
+                'destUrl': <?php echo '"' . $dest_url . '"'; ?>,
+                'AJAX_SUCCESS': 'SUCCESS',
+                'AJAX_FAILURE': 'FAILURE'
             };
             
             /**
@@ -73,37 +75,43 @@
              * Make an ajax call to the server and check whether the user's credentials are right. 
              * If yes then redirect him to his desired page, otherwise display a message.
              */
-            $('#login').click(function() {
-                var postUrl = GlobalVariables.baseUrl . 'user/ajax_check_login';
+            $('#login-form').submit(function() {
+                event.preventDefault(); 
+                
+                var postUrl = GlobalVariables.baseUrl + 'user/ajax_check_login';
                 var postData = {
                     'username': $('#username').val(),
                     'password': $('#password').val()
                 };
                 
+                $('.alert').addClass('hidden');
+        
                 $.post(postUrl, postData, function(response) {
                     //////////////////////////////////////////////////
                     console.log('Check Login Response: ', response);
                     //////////////////////////////////////////////////
                     
-                    if (response == true) {
-                        location(GlobalVariables.destUrl);
+                    if (!GeneralFunctions.handleAjaxExceptions(response)) return;
+                    
+                    if (response == GlobalVariables.AJAX_SUCCESS) {
+                        window.location.href = GlobalVariables.destUrl;
                     } else {
                         $('.alert').text('Login failed, please enter the correct credentials '
                             + 'and try again.');
                         $('.alert').removeClass('hidden');
                     }
-                });
+                }, 'json');
             });
         });
     </script>
 </head>
 <body>
     <div id="login-frame" class="frame-container">
-        <h2>Login Required</h2>
-        <p>Welcome! You will need to login in order to view this page.</p>  
+        <h2>Backend Section</h2>
+        <p>Welcome! You will need to login in order to view backend pages.</p>  
         <hr>
         <div class="alert hidden"></div>  
-        <form>
+        <form id="login-form">
             <label for="username">Username</label>
             <input type="text" id="username" placeholder="Enter your username here ..." />
             
@@ -112,7 +120,7 @@
             
             <br><br>
             
-            <button type="button" id="login" class="btn btn-primary btn-large">Login</button> 
+            <button type="submit" id="login" class="btn btn-primary btn-large">Login</button> 
             
             <a href="<?php echo $base_url; ?>user/forgot_password" class="forgot-password">Forgot Your Password?</a>
         </form>
diff --git a/src/application/views/user/logout.php b/src/application/views/user/logout.php
index b6eddc13..f6d8af5c 100644
--- a/src/application/views/user/logout.php
+++ b/src/application/views/user/logout.php
@@ -1,7 +1,78 @@
-<?php
-
-/*
- * To change this template, choose Tools | Templates
- * and open the template in the editor.
- */
-?>
+<!DOCTYPE html>
+<html>
+<head>
+    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
+    
+    <?php // INCLUDE JS FILES ?>
+    <script 
+        type="text/javascript" 
+        src="<?php echo $this->config->base_url(); ?>assets/js/libs/jquery/jquery.min.js"></script>
+    <script 
+        type="text/javascript" 
+        src="<?php echo $this->config->base_url(); ?>assets/js/libs/bootstrap/bootstrap.min.js"></script>   
+        
+    <?php // INCLUDE CSS FILES ?>
+    <link 
+        rel="stylesheet" 
+        type="text/css" 
+        href="<?php echo $this->config->base_url(); ?>assets/css/libs/bootstrap/bootstrap.css">
+    <link 
+        rel="stylesheet" 
+        type="text/css" 
+        href="<?php echo $this->config->base_url(); ?>assets/css/libs/bootstrap/bootstrap-responsive.css">
+    
+    <?php // SET FAVICON FOR PAGE ?>
+    <link 
+        rel="icon" 
+        type="image/x-icon" 
+        href="<?php echo $this->config->base_url(); ?>assets/images/favicon.ico">
+    
+    <style>
+        body {
+            background-color: #CAEDF3;
+        }
+        
+        #logout-frame {
+            width: 630px;
+            margin: 150px auto 0 auto;
+            background: #FFF;
+            border: 1px solid #DDDADA;
+            padding: 70px;
+        }
+        
+        #login-icon {
+            float: right;
+            margin-top: 17px;
+        }
+        
+        label {
+            font-weight: bold;
+        }
+        
+        .btn {
+            margin-right: 10px;
+        }
+    </style>
+</head>
+<body>
+    <div id="logout-frame" class="frame-container">
+        <h3>Logout</h3>
+        <p>
+            You have been successfully logged out! Click on one of the following buttons to 
+            navigate to a different page.
+        </p>  
+        
+        <br>
+        
+        <a href="<?php echo $this->config->base_url(); ?>" class="btn btn-primary btn-large">
+            <i class="icon-calendar icon-white"></i>
+            Book Appointment
+        </a>
+        
+        <a href="<?php echo $this->config->base_url(); ?>backend" class="btn btn-danger btn-large">
+            <i class="icon-wrench icon-white"></i>
+            Backend Section
+        </a>
+    </div>
+</body>
+</html>
\ No newline at end of file
diff --git a/src/assets/css/backend.css b/src/assets/css/backend.css
index d1a45a5d..aa1c5779 100644
--- a/src/assets/css/backend.css
+++ b/src/assets/css/backend.css
@@ -160,7 +160,7 @@ body .modal-header h3 {
 }
 
 #calendar .fc-header-title h2 {
-    font-size: 22px;
+    font-size: 20px;
     margin: 0px;
     line-height: 32px;
 }
diff --git a/src/assets/js/backend.js b/src/assets/js/backend.js
index 99b32ed7..561b26ab 100644
--- a/src/assets/js/backend.js
+++ b/src/assets/js/backend.js
@@ -25,10 +25,6 @@ var Backend = {
     /**
      * Backend Constants
      */
-    EXCEPTIONS_TITLE: 'Unexpected Issues',
-    EXCEPTIONS_MESSAGE: 'The operation could not complete due to unexpected issues. ',
-    WARNINGS_TITLE: 'Unexpected Warnings',
-    WARNINGS_MESSAGE: 'The operation completed but some warnings appeared. ',
     DB_SLUG_ADMIN: 'admin',
     DB_SLUG_PROVIDER: 'provider',
     DB_SLUG_SECRETARY: 'secretary',
@@ -91,31 +87,5 @@ var Backend = {
         
         $('#notification').html(notificationHtml);
         $('#notification').show('blind');
-    },
-            
-    /**
-     * All backend js code has the same way of dislaying exceptions that are raised on the
-     * server during an ajax call. 
-     * 
-     * @param {object} response Contains the server response. If exceptions or warnings are 
-     * found, user friendly messages are going to be displayed to the user.
-     * @returns {bool} Returns whether the the ajax callback should continue the execution or
-     * stop, due to critical server exceptions.
-     */
-    handleAjaxExceptions: function(response) {
-        if (response.exceptions) {
-            response.exceptions = GeneralFunctions.parseExceptions(response.exceptions);
-            GeneralFunctions.displayMessageBox(Backend.EXCEPTIONS_TITLE, Backend.EXCEPTIONS_MESSAGE);
-            $('#message_box').append(GeneralFunctions.exceptionsToHtml(response.exceptions));
-            return false;
-        }
-
-        if (response.warnings) {
-            response.warnings = GeneralFunctions.parseExceptions(response.warnings);
-            GeneralFunctions.displayMessageBox(Backend.WARNINGS_TITLE, Backend.WARNINGS_MESSAGE);
-            $('#message_box').append(GeneralFunctions.exceptionsToHtml(response.warnings));
-        }
-        
-        return true;
     }
 };
\ No newline at end of file
diff --git a/src/assets/js/backend_services.js b/src/assets/js/backend_services.js
index c7d52627..1c940324 100644
--- a/src/assets/js/backend_services.js
+++ b/src/assets/js/backend_services.js
@@ -300,7 +300,7 @@ var BackendServices = {
             console.log('Update Available Categories Response:', response);
             ///////////////////////////////////////////////////////////////
             
-            if (!Backend.handleAjaxExceptions(response)) return;
+            if (!GeneralFunctions.handleAjaxExceptions(response)) return;
             
             GlobalVariables.categories = response;
             var $select = $('#service-category');
@@ -334,7 +334,7 @@ ServicesHelper.prototype.save = function(service) {
     
     $.post(postUrl, postData, function(response) {
         console.log('Save Service Response:', response);
-        if (!Backend.handleAjaxExceptions(response)) return;
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         
         Backend.displayNotification('Service saved successfully!');
         BackendServices.helper.resetForm();
@@ -356,7 +356,7 @@ ServicesHelper.prototype.delete = function(id) {
         console.log('Delete service response:', response);
         ////////////////////////////////////////////////////
         
-        if (!Backend.handleAjaxExceptions(response)) return;
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         
         Backend.displayNotification('Service deleted successfully!');
         
@@ -439,7 +439,7 @@ ServicesHelper.prototype.filter = function(key) {
         console.log('Filter services response:', response);
         /////////////////////////////////////////////////////
         
-        if (!Backend.handleAjaxExceptions(response)) return;
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
 
         BackendServices.helper.filterResults = response;
         $('#services .filter-results').html('');
@@ -492,7 +492,7 @@ CategoriesHelper.prototype.filter = function(key) {
         console.log('Filter Categories Response:', response);
         ///////////////////////////////////////////////////////
         
-        if (!Backend.handleAjaxExceptions(response)) return;
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         
         BackendServices.helper.filterResults = response;
         $('#categories .filter-results').html('');
@@ -518,7 +518,7 @@ CategoriesHelper.prototype.save = function(category) {
         console.log('Save Service Category Response:', response);
         ///////////////////////////////////////////////////////////
         
-        if (!Backend.handleAjaxExceptions(response)) return;
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         
         Backend.displayNotification('Service saved successfully!');
         BackendServices.helper.resetForm();
@@ -541,7 +541,7 @@ CategoriesHelper.prototype.delete = function(id) {
         console.log('Delete category response:', response);
         ////////////////////////////////////////////////////
         
-        if (!Backend.handleAjaxExceptions(response)) return;
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         
         Backend.displayNotification('Category deleted successfully!');
         
diff --git a/src/assets/js/backend_settings.js b/src/assets/js/backend_settings.js
index 130721f1..da0a670c 100644
--- a/src/assets/js/backend_settings.js
+++ b/src/assets/js/backend_settings.js
@@ -394,7 +394,7 @@ SystemSettings.prototype.save = function(settings) {
         console.log('Save General Settings Response:', response);
         ///////////////////////////////////////////////////////////
         
-        if (!Backend.handleAjaxExceptions(response)) return;
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
        
         Backend.displayNotification('Settings saved successfully!');
     }, 'json');
@@ -520,7 +520,6 @@ UserSettings.prototype.get = function() {
         'notes': $('#notes').val(),
         'settings': {
             'username': $('#username').val(),
-            'password': $('#password').val(),
             'notifications': $('#user-notifications').hasClass('active')
         }
     };
@@ -555,7 +554,7 @@ UserSettings.prototype.save = function(settings) {
         console.log('Save User Settings Response: ', response);
         //////////////////////////////////////////////////////////
         
-        if (!Backend.handleAjaxExceptions(response)) return;
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         Backend.displayNotification('Settings saved successfully!');
         
     }, 'json');
diff --git a/src/assets/js/backend_users.js b/src/assets/js/backend_users.js
index c29040aa..5d7782ad 100644
--- a/src/assets/js/backend_users.js
+++ b/src/assets/js/backend_users.js
@@ -2,9 +2,12 @@
  * This namespace handles the js functionality of the users backend page. It uses three other
  * classes (defined below) in order to handle the admin, provider and secretary record types. 
  * 
- * @namespace BackendUsers.
+ * @namespace BackendUsers
  */
 var BackendUsers = {
+    MIN_PASSWORD_LENGTH: 7, 
+    
+    
     /**
      * Contains the current tab record methods for the page.
      * 
@@ -76,7 +79,7 @@ var BackendUsers = {
                     console.log('Get all db providers response:', response);
                     //////////////////////////////////////////////////////////
                     
-                    if (!Backend.handleAjaxExceptions(response)) return;
+                    if (!GeneralFunctions.handleAjaxExceptions(response)) return;
                     
                     GlobalVariables.providers = response;
                     
@@ -95,6 +98,26 @@ var BackendUsers = {
             $('.filter-key').val('');
         });
         
+        $('#admin-username').focusout(function() {
+            // Validate username. 
+            var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_validate_username';
+            var postData = { 
+                'username': $('#admin-username').val(), 
+                'record_exists': ($('#admin-id').val() != '') ? true : false
+            };
+            $.post(postUrl, postData, function(response) {
+                ///////////////////////////////////////////////////////
+                console.log('Validate Username Response:', response);
+                ///////////////////////////////////////////////////////
+                if (!GeneralFunctions.handleAjaxExceptions(response)) return;
+                if (!response) {
+                    $('#admin-username').css('border', '2px solid red');
+                    $('#admins .form-message').text('Username already exists.');
+                    $('#admins .form-message').show();
+                }
+            }, 'json');
+        });
+        
         /**
          * Event: Filter Admins Button "Click"
          * 
@@ -113,8 +136,8 @@ var BackendUsers = {
          * Display the selected admin data to the user.
          */
         $(document).on('click', '.admin-row', function() {
-            if ($('#admin .filter-admins').prop('disabled')) {
-                $('#admin .filter-results').css('color', '#AAA');
+            if ($('#admins .filter-admins').prop('disabled')) {
+                $('#admins .filter-results').css('color', '#AAA');
                 return; // exit because we are currently on edit mode
             }
             
@@ -243,8 +266,8 @@ var BackendUsers = {
          * Display the selected provider data to the user.
          */
         $(document).on('click', '.provider-row', function() {
-            if ($('#provider .filter-providers').prop('disabled')) {
-                $('#provider .filter-results').css('color', '#AAA');
+            if ($('#providers .filter-providers').prop('disabled')) {
+                $('#providers .filter-results').css('color', '#AAA');
                 return; // exit because we are currently on edit mode
             }
             
@@ -383,8 +406,8 @@ var BackendUsers = {
          * Display the selected secretary data to the user.
          */
         $(document).on('click', '.secretary-row', function() {
-            if ($('#secretary .filter-secretaries').prop('disabled')) {
-                $('#secretary .filter-results').css('color', '#AAA');
+            if ($('#secretaries .filter-secretaries').prop('disabled')) {
+                $('#secretaries .filter-results').css('color', '#AAA');
                 return; // exit because we are currently on edit mode
             }
             
@@ -522,9 +545,9 @@ var AdminsHelper = function() {
  * then the update operation is going to be executed.
  */
 AdminsHelper.prototype.save = function(admin) {
-    //////////////////////////////////////////
+    ////////////////////////////////////////////
     console.log('Admin data to save:', admin);
-    //////////////////////////////////////////
+    ////////////////////////////////////////////
     
     var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_save_admin';
     var postData = { 'admin': JSON.stringify(admin) };
@@ -533,7 +556,7 @@ AdminsHelper.prototype.save = function(admin) {
         ////////////////////////////////////////////////
         console.log('Save Admin Response:', response);
         ////////////////////////////////////////////////
-        if (!Backend.handleAjaxExceptions(response)) return;
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         Backend.displayNotification('Admin saved successfully!');
         BackendUsers.helper.resetForm();
         BackendUsers.helper.filter($('#admins .filter-key').val());
@@ -550,10 +573,10 @@ AdminsHelper.prototype.delete = function(id) {
     var postData = { 'admin_id': id };
     
     $.post(postUrl, postData, function(response) {
-        ////////////////////////////////////////////////////
+        //////////////////////////////////////////////////
         console.log('Delete admin response:', response);
-        ////////////////////////////////////////////////////
-        if (!Backend.handleAjaxExceptions(response)) return;
+        //////////////////////////////////////////////////
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         Backend.displayNotification('Admin deleted successfully!');
         BackendUsers.helper.resetForm();
         BackendUsers.helper.filter($('#admins .filter-key').val());
@@ -589,6 +612,12 @@ AdminsHelper.prototype.validate = function(admin) {
             throw 'Passwords mismatch!';
         }
         
+        if ($('#admin-password').val().length < BackendUsers.MIN_PASSWORD_LENGTH) {
+            $('#admin-password, #admin-password-confirm').css('border', '2px solid red');
+            throw 'Password must be at least ' + BackendUsers.MIN_PASSWORD_LENGTH 
+                    + ' characters long.';
+        }
+        
         // Validate user email.
         if (!GeneralFunctions.validateEmail($('#admin-email').val())) {
             $('#admin-email').css('border', '2px solid red');
@@ -657,11 +686,11 @@ AdminsHelper.prototype.filter = function(key) {
     var postData = { 'key': key };
     
     $.post(postUrl, postData, function(response) {
-        /////////////////////////////////////////////////////
+        ///////////////////////////////////////////////////
         console.log('Filter admins response:', response);
-        /////////////////////////////////////////////////////
+        ///////////////////////////////////////////////////
         
-        if (!Backend.handleAjaxExceptions(response)) return;
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         
         BackendUsers.helper.filterResults = response;
         
@@ -705,18 +734,18 @@ var ProvidersHelper = function() {
  * then the update operation is going to be executed.
  */
 ProvidersHelper.prototype.save = function(provider) {
-    //////////////////////////////////////////
+    //////////////////////////////////////////////////
     console.log('Provider data to save:', provider);
-    //////////////////////////////////////////
+    //////////////////////////////////////////////////
     
     var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_save_provider';
     var postData = { 'provider': JSON.stringify(provider) };
     
     $.post(postUrl, postData, function(response) {
-        ////////////////////////////////////////////////
+        ///////////////////////////////////////////////////
         console.log('Save Provider Response:', response);
-        ////////////////////////////////////////////////
-        if (!Backend.handleAjaxExceptions(response)) return;
+        ///////////////////////////////////////////////////
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         Backend.displayNotification('Provider saved successfully!');
         BackendUsers.helper.resetForm();
         BackendUsers.helper.filter($('#providers .filter-key').val());
@@ -733,10 +762,10 @@ ProvidersHelper.prototype.delete = function(id) {
     var postData = { 'provider_id': id };
     
     $.post(postUrl, postData, function(response) {
-        ////////////////////////////////////////////////////
+        /////////////////////////////////////////////////////
         console.log('Delete provider response:', response);
-        ////////////////////////////////////////////////////
-        if (!Backend.handleAjaxExceptions(response)) return;
+        /////////////////////////////////////////////////////
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         Backend.displayNotification('Provider deleted successfully!');
         BackendUsers.helper.resetForm();
         BackendUsers.helper.filter($('#providers .filter-key').val());
@@ -772,12 +801,34 @@ ProvidersHelper.prototype.validate = function(provider) {
             throw 'Passwords mismatch!';
         }
         
+        if ($('#provider-password').val().length < BackendUsers.MIN_PASSWORD_LENGTH) {
+            $('#provider-password, #provider-password-confirm').css('border', '2px solid red');
+            throw 'Password must be at least ' + BackendUsers.MIN_PASSWORD_LENGTH 
+                    + ' characters long.';
+        }
+        
         // Validate user email.
         if (!GeneralFunctions.validateEmail($('#provider-email').val())) {
             $('#provider-email').css('border', '2px solid red');
             throw 'Invalid email address!';
         }
         
+         // Validate username. 
+        var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_validate_username';
+        var postData = { 
+            'username': $('#provider-username').val(), 
+            'record_exists': ($('#provider-id').val() != '') ? true : false
+        };
+        $.post(postUrl, postData, function(response) {
+            ///////////////////////////////////////////////////////
+            console.log('Validate Username Response:', response);
+            ///////////////////////////////////////////////////////
+            if (!GeneralFunctions.handleAjaxExceptions(response)) return;
+            if (!response) {
+                throw('Username already exists, please enter another one and try again.');
+            }
+        });
+        
         return true;
     } catch(exc) {
         $('#providers .form-message').text(exc);
@@ -851,11 +902,11 @@ ProvidersHelper.prototype.filter = function(key) {
     var postData = { 'key': key };
     
     $.post(postUrl, postData, function(response) {
-        /////////////////////////////////////////////////////
+        //////////////////////////////////////////////////////
         console.log('Filter providers response:', response);
-        /////////////////////////////////////////////////////
+        //////////////////////////////////////////////////////
         
-        if (!Backend.handleAjaxExceptions(response)) return;
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         
         BackendUsers.helper.filterResults = response;
         
@@ -899,18 +950,18 @@ var SecretariesHelper = function() {
  * then the update operation is going to be executed.
  */
 SecretariesHelper.prototype.save = function(secretary) {
-    //////////////////////////////////////////
+    ////////////////////////////////////////////////////
     console.log('Secretary data to save:', secretary);
-    //////////////////////////////////////////
+    ////////////////////////////////////////////////////
     
     var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_save_secretary';
     var postData = { 'secretary': JSON.stringify(secretary) };
     
     $.post(postUrl, postData, function(response) {
-        ////////////////////////////////////////////////
+        ////////////////////////////////////////////////////
         console.log('Save Secretary Response:', response);
-        ////////////////////////////////////////////////
-        if (!Backend.handleAjaxExceptions(response)) return;
+        ////////////////////////////////////////////////////
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         Backend.displayNotification('Secretary saved successfully!');
         BackendUsers.helper.resetForm();
         BackendUsers.helper.filter($('#secretaries .filter-key').val());
@@ -927,10 +978,10 @@ SecretariesHelper.prototype.delete = function(id) {
     var postData = { 'secretary_id': id };
     
     $.post(postUrl, postData, function(response) {
-        ////////////////////////////////////////////////////
+        //////////////////////////////////////////////////////
         console.log('Delete secretary response:', response);
-        ////////////////////////////////////////////////////
-        if (!Backend.handleAjaxExceptions(response)) return;
+        //////////////////////////////////////////////////////
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         Backend.displayNotification('Secretary deleted successfully!');
         BackendUsers.helper.resetForm();
         BackendUsers.helper.filter($('#secretaries .filter-key').val());
@@ -966,12 +1017,34 @@ SecretariesHelper.prototype.validate = function(secretary) {
             throw 'Passwords mismatch!';
         }
         
+        if ($('#secretary-password').val().length < BackendUsers.MIN_PASSWORD_LENGTH) {
+            $('#secretary-password, #secretary-password-confirm').css('border', '2px solid red');
+            throw 'Password must be at least ' + BackendUsers.MIN_PASSWORD_LENGTH 
+                    + ' characters long.';
+        }
+        
         // Validate user email.
         if (!GeneralFunctions.validateEmail($('#secretary-email').val())) {
             $('#secretary-email').css('border', '2px solid red');
             throw 'Invalid email address!';
         }
         
+         // Validate username. 
+        var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_validate_username';
+        var postData = { 
+            'username': $('#secretary-username').val(), 
+            'record_exists': ($('#secretary-id').val() != '') ? true : false
+        };
+        $.post(postUrl, postData, function(response) {
+            ///////////////////////////////////////////////////////
+            console.log('Validate Username Response:', response);
+            ///////////////////////////////////////////////////////
+            if (!GeneralFunctions.handleAjaxExceptions(response)) return;
+            if (!response) {
+                throw('Username already exists, please enter another one and try again.');
+            }
+        });
+        
         return true;
     } catch(exc) {
         $('#secretaries .form-message').text(exc);
@@ -1045,11 +1118,11 @@ SecretariesHelper.prototype.filter = function(key) {
     var postData = { 'key': key };
     
     $.post(postUrl, postData, function(response) {
-        /////////////////////////////////////////////////////
+        ////////////////////////////////////////////////////////
         console.log('Filter secretaries response:', response);
-        /////////////////////////////////////////////////////
+        ////////////////////////////////////////////////////////
         
-        if (!Backend.handleAjaxExceptions(response)) return;
+        if (!GeneralFunctions.handleAjaxExceptions(response)) return;
         
         BackendUsers.helper.filterResults = response;
         
diff --git a/src/assets/js/general_functions.js b/src/assets/js/general_functions.js
index ef5d6a41..14f91457 100644
--- a/src/assets/js/general_functions.js
+++ b/src/assets/js/general_functions.js
@@ -6,6 +6,14 @@
  * @namespace GeneralFunctions
  */
 var GeneralFunctions = {
+    /**
+     * General Functions Constants
+     */
+    EXCEPTIONS_TITLE: 'Unexpected Issues',
+    EXCEPTIONS_MESSAGE: 'The operation could not complete due to unexpected issues. ',
+    WARNINGS_TITLE: 'Unexpected Warnings',
+    WARNINGS_MESSAGE: 'The operation completed but some warnings appeared. ',
+    
     /**
      * This functions displays a message box in
      * the admin array. It is usefull when user
@@ -234,5 +242,31 @@ var GeneralFunctions = {
      */
     ucaseFirstLetter: function(str){
         return str.charAt(0).toUpperCase() + str.slice(1);
+    },
+            
+    /**
+     * All backend js code has the same way of dislaying exceptions that are raised on the
+     * server during an ajax call. 
+     * 
+     * @param {object} response Contains the server response. If exceptions or warnings are 
+     * found, user friendly messages are going to be displayed to the user.
+     * @returns {bool} Returns whether the the ajax callback should continue the execution or
+     * stop, due to critical server exceptions.
+     */
+    handleAjaxExceptions: function(response) {
+        if (response.exceptions) {
+            response.exceptions = GeneralFunctions.parseExceptions(response.exceptions);
+            GeneralFunctions.displayMessageBox(GeneralFunctions.EXCEPTIONS_TITLE, GeneralFunctions.EXCEPTIONS_MESSAGE);
+            $('#message_box').append(GeneralFunctions.exceptionsToHtml(response.exceptions));
+            return false;
+        }
+
+        if (response.warnings) {
+            response.warnings = GeneralFunctions.parseExceptions(response.warnings);
+            GeneralFunctions.displayMessageBox(GeneralFunctions.WARNINGS_TITLE, GeneralFunctions.WARNINGS_MESSAGE);
+            $('#message_box').append(GeneralFunctions.exceptionsToHtml(response.warnings));
+        }
+        
+        return true;
     }
 };
\ No newline at end of file