Try re-uploading all files & folders – except the wp-content folder and your wp-config.php file – from a fresh download of WordPress.
Actually, it looks like PHP is not running on your server. You should contact your hosting provider.
I’m curious if you’re hosted by GoDaddy because one of their customers reported the same problem here an hour ago.
Thanks for the reply. @macmanx yes my site is hosted in godaddy. I actually have 2 wordpress sites that mysteriously went berserk at the same time. this is the first one and the other one is http://socialmediaextreme.info that now shows that the site is currently unavailable. I guess i’ll have to check this with them.
I’ll keep you updated and thanks for the suggestions.
@zedlav23: are both of your sites hosted on the same physical server, by any chance?