File Downloads Instead Of Loading Websites

I installed our webpanel in my unmanaged vps a month ago. Until now, all things worked fine. I have 2 user accounts and more than 10 websites in these accounts. Yesterday I added a domain and I got 'HTTP Test Page'. To resolve this, I tried rebuilding virtual hosts and apache config. But after that when I try to visit any domain in my primary account it downloads a file automatically instead of loading webpage in browser. The secondary account just works fine. Now all my websites in primary account are offline.

Domains:

1. whatsappvideos.ga
2. funnynewvideos.ga
3. youwemedia.ga

and few more. Kindly help me as soon as possible. Her's the example of auto download file. I think it is insex.php

<?php
/**
 * Front to the WordPress application. This file doesn't do anything, but loads
 * wp-blog-header.php which does and tells WordPress to load the theme.
 *
 * @package WordPress
 */

/**
 * Tells WordPress to load the WordPress theme and output it.
 *
 * @var bool
 */
define('WP_USE_THEMES', true);

/** Loads the WordPress Environment and Template */
require( dirname( __FILE__ ) . '/wp-blog-header.php' );

Try to recompile php also.

Try to recompile php also.

recompiled php, but still facing the same error. Is there is anyway to change user account of the websites? Secondary user websites just working fine.

did you restart Apache after php re compile
service httpd restart

have you installed any packages manually ?

You should also check this tutorial, and your htaccess, php.ini file
http://wiki.centos-webpanel.com/default-page-displayed-for-all-domains