After running World of warcraft, and after a few seconds (maybe 5-30), the screen goes blank and the monitor acts like its not getting a signal. My computer is still running but won't react to any buttons I press (at least not on the screen). I think it may be my graphics card overheating. I haven't had this problem before, but this morning my computer was making a loud sound like a fan was clogged so I blew a bunch of dust out of my case. I have a 6600 GT by the way, and it has been working for quite a long time.