THe game is pretty demanding, it's probably bringing out gremlins in your computer you weren't aware of because it hadn't been taxed so hard.

Run a memory test, a cpu test, and a gpu test, they can all be found with the google. If the computer crashes during one of them, that's probably what's faulty. If not, I'd look to your power supply. Check your voltages in the bios and make sure they're within spec.