Why does my laptop power down as soon as it starts?

If it runs for a while and then starts doing this, it's likely overheating. Modern systems have a thermal safety where the processor itself will deactivate above a safe level. Check the vents and clean them out with canned air.

If that isn't the case, first disconnect any and all external devices (including USB nubs, etc) and try powering it back on. If that doesn't fix the problem, try removing all but one RAM stick and removing the hard drive and CD/DVD ROM. Try turning it on then.

If that still doesn't work, remove ALL the RAM and check for a beep code. If you get one, you know the motherboard is at least still working enough to give a no-RAM code. Try alternating the RAM sticks to see if it works.

One of the first and most likely reasons your computer is shutting off randomly, especially when you’re playing a game, is an overheating issue. This is the bane of most computers, especially laptops, since the heat has nowhere to go. Fans that are in peerless working order are critical in aiding this issue.

This is such a common and important issue in fact that most computers now have a built-in mechanism that will shut off your computer if any of the components become too hot. Consider this your fairy mother protecting your expensive electronic device.

What you want to do to overcome this is to figure out what is causing the heat, and dirty fans are most likely the culprit. You’ll want to “look at your video card fans, case fans and processor fans” to see if any of them are squealing. If one is, that probably means one of them is broken.