You may be having more then one issue with your pc. For the game crashes and shut down could be the gpu running hot or weak power supply. A lot of gpu need programs that you can set a fan profile. Most gpu vendor have there cards bios and fan driver default to 30-40 percent...under heavy game loads sometime that fan speed can't keep up with the heat. On windows running slow run hdtune and read your hard drive smart info for any warning and run hd vendor test tools. If your hard drive looks fine try running memtest.