Windows start, scroll down to admin tools. Event viewer will be listed there. It's part of Windows that takes notice of any hiccups like drivers not starting, voltages out of whack, critical errors etc. It's especially important because it records every BSOD and other sudden shutdowns not initiated by the user logging off.
You should be using a can of compressed air when cleaning out a pc, it has a straw that let's you get right down into the vanes of the cou/gpu heatsinks and blow out all the debris that could be clogged there. Just cleaning off the fans doesn't do anything for the heatsinks ability to get rid of heat if it's coated in dust. Most decent cases will have a dust filter on any intake fan, that includes the fan on the bottom for the psu. If those filters get clogged, you get lousy airflow, so little air is used by the fan resulting in higher temps. If the inside of the psu is caked in dust, its like being insulated in a dust blanket and won't cool off. Cheaper psus can and do loose their ability to supply a good working output at anything over 30°C. Better psus go to 40°C and the best go to 50°C. If your psu is reaching 30°C inside, you could be loosing enough output on the 12v rail that it's not supplying enough to keep the gpu running, so the gpu freezes then shutdown.
A thorough cleaning of a pc should be done at least every 3 months, more in dusty areas and should run at least an hour. It's not a weekly 3 minute blowout of the fans.