I have just finished building a new system with an i5 overclocked to 4Ghz bundle. I have an ATI 5850 as the gfx card. I left my machine running last night to download dirt2 from steam. There was no issues all night running for 10 hours. Temperatures were 40 max. Now when I run dirt2 it crashes before the intro screens are done. Flight Sim X crashes constantly, 3DMark demos crash. What on earth would be wrong? It seems like everything is fine until gfx card gets under a load. Does this sound like a wonky card? I have installed 10.1 catalyst drivers. Really getting annoyed with this!