Hello
I am hosted with hostgator.. this is what has happened..
I was in cpanel, EDITING a file (css). I pressed save on a CSS file (nothing to do with WORDPRESS). I then REFRESHED my browser page. It then loaded the standard bog standard wordpress theme. I was like wtf? I then tried logging into the admin panel and it said I had no permissions and I searched for the error code, someone said the error is because my wp-includes was not chmodded.. I went to cpanel again in my tabs, and wp-includes and wp-content and wp-admin had no chmod set... I was like how did that happen.. I then put them back to 0755 and now wordpress has deleted my old theme... my posts are still there but my theme has gone.. I used the default theme as my theme as I overwrote it...