If your graphics card overheats, but not any other component, what happens? Does it freeze your computer, forcing you to restart, or would it just shut down your computer? I believe my gpu may be overheating if it is the first case, because that's what happens to me sometimes when I'm playing a game. I also believe it's my gpu because when I restart it, sometimes my monitor doesn't detect anything and goes to sleep, yet I'll still hear the windows start up sound play. If I wait a bit then restart, everything works fine.