When playing PC games continuously for a long time, the computer randomly crashes or reverts to the desktop.

  Random crashes in games can be the result of a few different problems. Typically, it's heat, a driver, the Windows install, a virus, a software incompatibility, or a problem with the game.

  The first thing you should do is check for a patch for any of your games that are crashing. It seems like common sense, but frequently we receive complaints from people trying to run games that have been patches available but never downloaded. 

  Once you've updated your game, you may need to update your video card and chipset drivers. Download the latest video card driver from the company that manufactured your card's chipset.

  You should also check for newer drivers for your motherboard's chipset whenever you update your video card drivers. Outdated motherboard chipset drivers are one of the main causes of general system instability.

  If you've updated all your hardware, but are still having problems, you may have a heat issue. Open your case and look at your video card. Is there another card right next to it? If there is, you should consider moving that card to another slot. A card directly next to a high-end video card can disrupt airflow enough to cause overheating issues with today's top-of-the-line video cards.

  If freeing the neighboring slot doesn't alleviate your problem, try adding a fan that fits into one of your PCI slots and exhausts hot air from the bottom of your PC.