I think you're looking at a wipe and reload. I had that problem with MCE and no matter WHAT I did I couldn't fix it. I tried several different driver versions, Cat Cleaner, Driver Cleaner and about a million other things. And it seemed kinda random too. I did nearly the exact same install procedure on several installs and had problems on two. Then again I had another card in the system at the time too...
Try uninstalling all your ATI drivers, chipset drivers, video card drivers....and reinstall them all. If this doesn't work you might just need a wipe and reload. Sorry I don't have much better advice man. Goodluck!