Vista - Video Issues

Greetings everyone,
I just recently upgraded to DirectX 9.0c (to play the game Call of Duty 4)
and I am now having my display driver crash often while just hanging out in
Windows (let alone playing the game, that is a whole 'nother story). It is
even forcing the computer to reboot spontaneously. I also see funny lines on
my desktop and flashes in screensaver often as well. Basically my compuer is
possessed - can you help?

A few other tidbits, I have also installed the to vista updates with no luck
there. And I have also updated my nvidia card drivers to the latest
edition... still no luck.

Thanks so much in advance for your help.
Taylor