My PC just started shutting itself off when i start playing games i used to play months with.I didn't change anything in it. After shutting off, the lights on my keyboard stay lit but all else is shut off. I have no problem booting it back, but cant play.

Reinstall/update drivers for you video card.

If your computer shot off, you may have several things that you want to check. You may want to install gaming ram, a CPU cooler, also check CPU heat transfering compound, add some. Also your on and off switch may not be working properly, turn it on and disconnect on and off cable/switch. If you are a gamer also you might want to think about upgrading your video card. Check your chip set heat sink, if it is glue down, also have a compound and may be held down by a wire attached to the motherboard by some u shape clips, make sure they have all clips on the motherboard, that can be causing you a problem. Also check for memory conflicts, that can make your computer to shot off, it happened to me with a webcam. I hope that help you. 0 Gravity

Check for viruses/spyware. also it is possible you've got an overheating problem. Try putting thermal compound between your processer and heatsink and clear all dust, dirt thats gluttered up inside. check all your cooling system is functioning ok see if this helps.

I've seen similar problems. Most of them seem to be related either to over heating or loose memory boards. Cleaning dust from the fans and heat sinks usually helps as mentioned in other anwers. When cleaning the computer make sure that you take proper precautions to avoid static discharge. Un plug the computer and ground the chassis, and your self to the chassis before you handle the circuit boards especially the memory cards and microprocessor. If pins are corroded, use a clean eraser and contact cleaner. Don't use abrasives. If you use a game controller or joystick, the drivers may need updated or the the controller could be faulty.

My computer acted this way, until the Trojan virus finally took over. Run a virus check. You may wake up tomorrow morning and face a big red trojan on your computer screen. If you downloaded those games a while back, the virus has probably been stored in the download and just waiting for you to make another visit.