My C2Q System with it's GTX 260 came crashing down after updating to the GeForce 3.20.18 driver.
It now will only run on the onboard Intel G41 chip, refusing to work with the nVidia driver,
no matter which nVidia card I install -mind you: without the 3.20.18 driver the cards will work (but won't crunch).

Anybody else these experiences with nVidia's latest?