I've been having the above problem for a while now. It occurs randomly and unpredictably, having just now had my first crash in over a week. The PC becomes unresponsive and requires a hard reset via the power switch. Temperatures are fine - The CPU rarely exceeds 45°C, and the GPU appears to plateau at around 70°C. There are never any bluescreens, and as far as I can see, the only errors in event viewer are standard kernel power errors.
I have tried:
-Fresh install of video drivers
-Fresh install of sound drivers
-Removal of third party sound drivers entirely
-Several passes of memtest86
-Several hours of furmark stress testing
Any help would be amazing. Thanks in advance for your time.
Speccy snapshot: http://speccy.piriform.com/results/7RLaNEVinEg1oKMnSGadE7r