Your GPU even outs to 80C at high load. From what I'm reading online this seems to be a pretty good stable temperature and it means your fan is doing its job keeping it from going any higher. I personally can't see how this would be an overheating problem. The previous 95C as you mentioned though, is definitely pushing it, especially if it experiences that temperature over extended periods of time.
I want to note that from what I read online that was temperatures people experienced when they started doing some overclocking on their card (same exact model as yours). If yours isn't overclocked and still experiencing these temperatures...
Anyways, I've found a while back a pretty solid article on troubleshooting TDR failures like this
here. It does a good job explaining many of the causes for why it would do this. You'll wanna give it to a look.
I want to add, I noticed that at the time you posted the JCGriff Report, it said you were already using up around half your 4GB of RAM. These issues can be caused by RAM exhaustion (especially since much if not all graphics activity involves nonpaged pool, which can only be attached to RAM, never to paging file on disk). Windows 7 sets a maximum of nonpaged pool on RAM to 75% of the total RAM. If this gets exhausted, then these problems occur. There may be a process that's hogging memory and taking up nonpaged pool. These are
potential causes, so don't rule out the GPU.
In addition, I did remember you saying something about getting a replacement motherboard. Often motherboard problems can show up as anything else. Have you tried updating the
drivers for your motherboard, as well as the BIOS? In addition, if you have onboard video, uninstall the drivers for it and do whatever you can to prevent it from being active (turn it off on BIOS, etc.). I've seen video cards and onboard butting heads before on resources.