I have pretty much exactly the same problem. Spec. ATI HD 5770 ASUS M4A785D-M Phenom II x4 955 3,2 ghz DirectX 11 Brand new computer running Win 7 64-bit. Tried both Catalyst 10.2 and 10.3. Games work just fine, but the video on various players and codecs is all pixelated or grainy. It lagged...