There are a lot of nVidia owners complaining about these drivers. Use an older version to see if it solves your problem. I am still using 332.21 WHQL since they give me better performance than later releases. Don't use GeForce Experience. It causes more problems than its worth. When you install these drivers use Custom Install. Never use Express Install. Check the box for 'Clean Installation' and uncheck all other boxes except for PhysX and Video driver.
http://www.geforce.com/drivers
 

Okay, I'm beginning to think its not a software issue since I just had another crash. I loaded version 332.21 this morning and about 5 minutes ago I had a crash. I'll try and keep everyone updated and let you all know whats causing it.

If I had any overclocking, that would have been my first guess as to whats causing the problem. But since there is apparently so little you can do extra to the 660 (not the Ti) I never tweaked it. I only run PrecisionX for the fan controller and the occasional performance monitoring. And as of the second crash I disabled PrecisionX, so it hasn't been running for a few days.
 
Here is something strange, I found something that will crash it consistently. When I'm signed into gmail, at the top right of the screen there is a bell shaped icon (notification icon for something). When I click on it and try to interact with it I get a crash (successfully crashed twice in a row....yah, once was bad enough I know :) ). All this icon does is notify on activity (apparently YouTube activity). It doesn't try to link me to another page or anything, it just simply freezes for a split second then goes black. (I dont typically have any sort of notifications enabled, but thats a problem to address on a later date.) I just find it odd that something like this would cause a full graphics blackout.
 
Could I have a bum internet browser version? I recently (month or so ago) got the most recent version of FireFox (yes, FireFox :) ). All my auto update functions are off so I know I dont have anything newer than what I originally put on when I reloaded my OS 2 months ago.
 
Other than the one or two crashes I had during a game (was not an online game or a game tied to the internet) all the crashes since then have been when my browser was open. And as far as I can remember its been when I had Gmail open.
 
 

I'm running a Evga GTX 670 FTW. Tried a clean install of the latest Nvidia driver and it crashed my system half way through the install procedure and in the process taking out the W7 64 bit generic GPU driver, my restore points and left me at a 640x400 resolution. Didn't realize the default W7 GPU driver had been wiped out until I got a prompt with such and such files were missing.
 
After a lot of trial and error including running Windows Update among other machinations I got the driver installed I've been running since release in November.
 
I've never had a system crash installing any Nvidia driver to date. Whatever the reason I'm not about to chance trying to fix what isn't broken until the games I play require the latest driver.  

Im still using 335.23 with my current 650 Ti Boost, "RIP GTX 460" my 460 was 10x better than this 650 Ti, but the 460 was really bad about drivers just not working, at one time I was using a 12+ month old drivers.
 
Nvidia just dosent give a rats butt about quality drivers....