There is definitely a known issue with the latest version of DirectX (10.xx I believe) and CERTAIN versions of Nvidia drivers.

many people have had very good results by rolling back their Nvidia Drivers to an earlier version (including me, on my previous machine, I had to roll back my drivers to 5.something IIRC)- if you do search on the forums for Nvidia and CTD - you will probabably find more information about it than you really wanted to know..
*grin*

Good luck

DE