I had it recently, but only when playing Call of Juarez. I would get it literally within 5 minutes of playing when my overclock was 3.6ghz (450x8). I didnt do anything else but change the fsb and the multiplier to (333x9) and I have not seen it since. For me it had to do with the overclock, maybe for you too, but I dont know for sure.
I still have to mess with it, to see what the problem was, maybe the ram was not getting enough voltage to run at 900mhz (which is crap because I was running it at the recommended 2.1v for 900mhz). I will try to unlink it and run it at 900mhz and see if that causes that problem. If not, then it has to be the cpu, I will slowly increase the overclock until I start getting that crash.
If you are overclocked, you could try the same thing. It did it on my computer with all the drivers, so when I found a quick fix (lowering the oc) I installed the 174.51 drivers.
And also those Hotfixes don't fix up anything to with the Nvidia driver problem, mentioned above!!
Either a driver installation or update had a corrupt file or not installed and updated properly!
But a Driver Cleanup to clean left over registrys and etc will 100% take the problem away....Use Driver Cleanup Professional Ed. 7 which is available through guru3d.com. Then install the driver or update needed!