My laptop fan is running non stop, even when I use 10% or less CPU and even when I leave it alone for hours at a time. I come back, and it's still running. But the computer isn't even hot. Almost as soon as I turn my laptop on, the fan starts up and never stops. It's overheated a few times recently, resulting in spontaneous shut down of the machine all together. I had to wait a few minutes before I started it back up, and when I did, the fan started up almost immediately. Also, I set it to go into stand by mode on its own after an hour of non-use, and then into hibernation mode after 2 hours of non-use. But a few months ago, it stopped doing it on its own, and now I have to get up in the middle of the night and turn it off myself, for fear that the fan will run itself out. Keep in mind that this is an 8 month old laptop from Gateway.

i'll bet a sensor or transistor went south on you. you'll have to take it in for service, perhaps it's still under warranty.

How common is this in laptops, because my old one did the same thing after less than a year.

i've actually seen heat related damages in lots of cases recently, on account of the heat dissipated by today's more potent machines. usually the owner leaves thiers on a blanket or couch so the sides are at least partially blocked. sure enough, the thing locks up or shuts down and can't be revived.