If your site is getting hacked, I would first off delete your install directory, then follow the following links. You must be thorough or don't even bother - no honestly you must be thorough no joke, this has been said with much emphasis these days!
http://www.vbulletin.com/forum/blogs...vbulletin-site
http://www.vbulletin.com/forum/blogs...ve-been-hacked
http://www.vbulletin.com/forum/blogs...vbulletin-site __________________