After changing the usable themes and current theme in general settings (or preferences, forgot now) the whole site displays nothing. I've read that means an error. I have a feeling I may of "overloaded" the usable themes by selecting all of them, which is what I believed was how it worked. But then again it could be that I don't have the theme that I picked for the site. Regardless is there a way to manually change these settings?

I'm using version 2.0 if that helps.