IIRC - If I Remember Correctly.
Anyways, I would use DriverCleaner, go through all the steps, and then install the 71.84 WHQLs from NVIDIA. Those, IMHO (In My Humble Opinion), are the best out there. I have had ZERO problems with them, and in fact, they revealed flaws in the 67.66s that I had not previously noticed. The only "bug" that I can see with the 71.84s are that the temps are reported a bit too high, though the card isn't actually heating up, the drivers are just not reading the right temps from the temp sensor. Other than that, there is no problem that I can see.
USE DRIVERCLEANER!!!, that should fix your problem.