Ruined my Site?

I am having so many issues that I don’t know where to start. I’m hoping someone can help.

The main issue was that I went to update my wordpress site, finelines.org. The site loaded fine, but when I clicked on admin, I could not access the administration end of it. I thought it was my connection or something, but I contacted my host, and they found that:

We have noticed that the WordPress theme ‘ThemeOnly1’ that you are using for the website at the URL “http://finelines.org/” is corrupted and also that there are many plug-ins you are using within the relevant website.

We would request you to please re-upload the WordPress theme ‘ThemeOnly1’ from your end and then try to disable the plug-ins (one at a time). Once the WordPress theme issue is fixed; you would be able to login via the URL at “http://finelines.org/wp-login.php”. Please do the needful from your end.

So I went here: http://wpdude.com/theme-go-rogue and read about how to disable the theme. I tried to make it 000, and now the site won’t load at all, and the corrupt theme is no longer even showing up on my ftp list, so I don’t know what happened to it!

I also don’t know which plugins are corrupt or what to do about that.

More important… how did this happen? How do things just go corrupt?

So what can I do to salvage the site? I’m guessing all the content is still there. Is there a way to transfer the stuff I still have to an entirely new wordpress install? Would that work?

I’d have to rebuild the theme… or something.

How can I get the theme back? I didn’t delete it, I just changed the permissions. Why doesn’t the site load the default theme like it is supposed to?

Thanks for any suggestions.