play the game for like 3 minutes and then my computer just turns off!
What is happening to you sounds pretty bad, but finding the problem will take some work. There are two main routes to go: Spend Time or Spend Money. To me, computer shutting down sounds like an operating system problem or a hardware problem. So maybe your operating system has gone bonkers and needs a new install, or maybe some hardware is dying. This could be your hard drive, video card, but most likely your power supply unit.
- Go to manufacturer websites for hard drive, video card, motherboard, sound card, network card, and download drivers. Completely uninstall drivers for above hardware, then re-install fresh ones. If this doesn't work, then next step.
- Back up your data, unplug everything except speakers, monitor, mouse, keyboard, and re-install your operating system for a fresh, clean install. Then install ONLY Diablo 3 and see if this helps (this fixed my problems).
- Buy a new power supply, boot up, see if this fixes the problem.
- Try swapping out video cards.
- If you have spare hard drives, remove your old drive, install your operating system on the new one, and see if that helps.
There is no easy solution (besides buying brand new hardware and fresh install OS), but with some time you can fix it! :)