Have you updated your nVidia & DirectX drivers?
Have you updated the game to the newest version?
Sometimes these 3D games may crash when one of the graphics features doesn't work well with your particular video card or driver. Try lowering/turning off graphics features.
This link might help you:
http://www.terminally-incoherent.com...working-fixed/
I don't know about the other nVidia video cards, but on my 8400GS, the stupid PhysX component really messes up the video card, so I always install any newer drivers without the PhysX component.
Try going into the nVidia video card settings and disabling PhysX to see if that helps.
Try uninstalling & re-installing the game one more time. (Copy your saved games to another folder first, if you want to preserve them.)