I have a similar problem. My Nvidia Geforce 550 Ti driver (335.23) crashes after about an hour of playing. Time to crash varies and depends on the graphic settings. At low texture settings, a crash occurs rarely or not at all. On high settings more often.
The previous driver caused the same problems but before that everything worked fine.
In other games i have no problems with driver crashes and the temperature of the graphic card is slightly under 80 degrees. Same temperature as with other games.

I have a GTX 460 and no crashes with the experimental driver 331.93 This is the the most stable driver for my card. No crashes with any games / programs I use, since I use this specific driver. Maybe you want to test it.
Making a system restore point before messing with Nvidia graphics drivers of all kind is recommended.

Make sure you uninstall the current driver completely for a clean install.

You can get the Driver here:

https://forums.geforce.com/default/topic/621899/geforce-drivers/desktop-internet-browser-freeze-or-tdr-thread-w-geforce-460-560-gpus-updated-11-20-13-see-page-50-/post/4024328/#4024328

I was able to resolve this issue by downclocking my video cards core and memory frequency slightly in MSI Afterburner. Not sure if it was a hardware issue specific to my card or why it happened much more frequently in 44.12333800 than in 43.116251 but all good now :)