There are people having problems with the 11.2 release - no surprise there
Negative review here:
AMD Catalyst 11.2 Windows 7 Driver Analysis - Final Thoughts :: TweakTown USA Edition
I had problems with random freezes and crashes, even had my video cad not being recognized sometimes when I would boot up my computer.
I had to (in safe mode) uninstall all traces of ATI drivers, then reinstall 11.1, now everything seems to be fine.
Not everyone is having issues, a look at the amd forums shows mixed results, but maybe that is what is cuasing your problems too. try uninstalling the 11.2 and installing 11.1 or the 11.1a hotfix release.