The fan on the card is running constantly now and I can't get it to stop. Usually it will only rev up when playing a game or watching a video, but now it's running constantly, even when the monitors are asleep. The only way I can get it to stop is by putting the entire machine to sleep, and then it comes right back on after the machine is running again. I just recently blew all of the dust out of the tower and the card. Yet it's behaving like it's packed with dust. Any ideas? Is the card going bad?