Activated desktop effects in Ubuntu and resulted in black screen
 

I just recently (yesterday) installed Ubuntu (Hardy) and I was browsing around, looking for a way to lower my EXTREMELY high resolution, and I clicked an interesting button (or checked a box, can't remember which) which said "Activate desktop effects," or something along those lines. This resulted almost immediately in a permanent black screen. The black screen is functional... In that I can do things and click buttons and things happen (sounds etc) that I assume would happen all the same had there not been a black screen, but I can't get RID of it! It's very frustrating. Any suggestions?

Welcome to LQ!
What is happening when you reboot?What grafic card and how much RAM do you have?