To put it shortly. After long times of playing this game it will somehow RESTART my computer.
I have fiddled with the graphics a bit, thinking that it was a problem with the settings there and it fixed nothing. (I turned it from ULTRA to high)
I highly recommend capping your framerate, greatly lowering your video settings, getting a powerul cooling pad (if on laptop), and/or replacing your PC’s thermal paste.
Also make sure your fans are running/triggering when they’re supposed to. Many motherboards or motherboard companies have software/drivers free on their sites that allow you to customize when your fans turn on and at what temperatures they start or increase speed. If you don’t know what motherboard, there is a free and harmless program called Speccy that will tell you what parts you have installed, and then you can Google that motherboard to get your driver’s and software.