I'm not quite sure.. but me and my friends have installed the new catalyst drivers from ATI.. after my display, and my friend's display screwed up, once I up'd his refresh rate... I've come to the conclusion that these drivers are buggy.. IF this problem occurs, my suggestion is:
Uninstall the catalyst 4.1 drivers from your program list, then reinstall them, if this doesn't work.. take a version prior to 4.1, and install those.. IF you still would like to use the 4.1 drivers, i'd suggest consulting an ATI offical on this matter, and see if they can steer you through the problem.
-Liquid
I noticed too that the 'hide the refresh modes your monitor can not display' was gone and you could choose any mode. I found this weird and potentially dangerous, but I up'd it to 85 nonetheless, and it seems to have been working fine.
I'm for sure they are buggy now..