If you’ve disabled all plugins and switched back to the default Twenty Ten (or Twenty Eleven) theme and are still seeing this, then you’ve got a serious problem.
First of all, the JavaScript is horribly obfuscated. Second of all, with no plugins and a default theme, you should see the default layout of WordPress.
From the looks of things, someone has probably hacked your site.
I recommend you:
- Read this article in the Codex
- Reinstall WordPress
Update
I did some reverse-engineering on that JavaScript you linked to, and you have been hacked. It’s a compression script that uncompresses itself and calls window.eval() to execute its package.
The code adds a hidden iframe that loads content from a bad domain into your site. I’m not going to post the full details of the hack here, but it’s pretty bad.
In addition to reinstalling WordPress, I also highly recommend you change all of your server passwords:
- FTP
- SSH
- MySql
You might also want to work with a company like Sucuri – they specialize in malware protection and removal.