After trying all possible things I could think of I sill have the same problem. Every game (The Witcher, Need 4 Speed) I 've tried so far results in black frames. The games start ok but just after I start playing the screen goes black but the ingame music keeps playing. If I don't move my keyboard and mouse I'll get some visible frame's back. Usually just enough to be able to quit the game. System does not lockup or something. No blue screens either. All other software (Windows 7 & Vista ,Photoshop, Open Office, etc) behave normally. I have got a brand new system (just 1 week old when writing this) to play around with. Specs: Coolermaster CM690 Core i7 920 Club3d ATI 4850 512mb MSI X58 PRO OCZ 1Gb 12800 (1600) triple channel kit (3Gb total) Antec Earthwatts 650w Samsung spinpoint F1 640Gb Things I've tried so far: Firstly I Installed Windows 7 (Beta 64bit) and the ATI Catalyst drivers for windows 7 (Beta 64bit). Uninstalled Catalyst Beta and installed Catalyst 9.2 And updated everyting i could think of. No solution there. Then I started all over again this time round using Vista Ultimate. No solution there either. Is there somting I've missed or do I have to replace defective harware?