SOLVED! This has been solved by following this guide:
I'm running a freshly installed Ubuntu 11.10 and I just installed the ATI drivers from the ATI website and all went well. But when I log in, all I see is an empty desktop and the menu (Files, Edit, etc.). That's it! No launcher, no time, no indicators, no Unity, nothing!
I tried running aticonfig and got this: aticonfig: error while loading shared libraries: libGL.so.1: wrong ELF class: ELFCLASS32
I had to remember how to launch terminal to be able to launch Firefox.
Thank you :)