I have the exact same problem as the OP. I've tried all the solutions above but did not help.
Ill send in my dxdiag too.
Edit: I've tried verifying the integreity of the steam cache, it finds 1 file wrong and download that fast. Did not help though, tried two times, 1 file both times, still no luck.
Last edited by PzyCow; 05/11/10 08:45 PM.