could try running dxdiag (just type that in the search or run box off your start menu) to see if it notes anything fishy with your DirectX components.

Might be able to resolve it by running the old DX9 runtime installer, in case you are being plagued by the old missing DLL problem that rears it's ugly head occasionally:
http://www.microsoft.com/en-us/downl...ils.aspx?id=35

Otherwise, I'd double check to make sure you are running on the proper hardware (some systems have 2 GPU's, don't want to be using the Intel one), or you could have an issue with inadequate power or cooling for the graphics card.

Might be worth it to check your hard drive for errors as well.