Malicious Code - Website Disable I'm new to Drupal. My website has been disable due to malicious code found in 
/var/www/vhosts/domain.com/httpdocs/sites/all/themes/tao/tao/css.php

What should I remove in this file? 
http://pastebin.com/4xQixw13
You should remove the entire file.

Also,  this is not enough to fix your site.  I would recommend exporting your content and doing a fresh install, with a fully updated version of Drupal.