May not be able to get on in a while

Im having computer trouble, which is why i logged in and out a couple times last night. Every time a run a game (any game) I get a black screen and i have to restart it. Im assuming its overheating, and there doesnt seem to be much i can do about it. If anyone has an idea thatd be great, but otherwise i wont be able to get on until its fixed or i get a new computer.