Hello and welcome to the forum.
First did you create a restore point before trying to install the new drivers.
Here is a BSOD tutorial made by Brink that might be very helpful in finding what the problems is.
BSOD - Debugging a BSOD in Vista
Have you tried to uninstall the drivers for NVidia.
I would aslo check to see if there are any yellow flags in the device manager. If there are any flags those need to be updated first.
Click Start...
Control Panel...
Click System and Maintenace...
Click Device Manager...
Click view...
Click show hidden devices..
Then you can update them the drivers from there