I've recently bought a new computer which I assembled with a friend, but it seems I'm having problems running certain games. The problem lies in that TF2, CSS, Tribes:Ascend and 3DMark 11 sort of crashes when something 3D appears. The game minimizes itself or just goes black after 0-3 seconds and wont open again, but when it's "marked" on the taskbar I can still hear the sound. If I run the game in window mode the screen just becomes white. Minecraft works fine though.
I also reinstalled Windows 7 and all the drivers. But it didn't help at all.