Can you please tell us what games you are trying to play. What do you mean by your computer crashes? Do you get a Blue Screen of Death. If you do, can you please zip up and upload the contents of the C:\Windows\Minidump folder so that I can analyse it for you?
In the mean time, make sure all your games are fully updated. Update all your drivers, in particular your graphics card driver.
i have tried to play never winter nights, aion, and champions online and when my computer crashes it does not give the blue screen of death it doesn't even give an error report basically what happens is ill play the game for 10-30 min and the screen will freeze up then my computer automatically shuts down after 5 to 10 min sometimes i even have to shut off manual