I have a dell Dimension 4600c desktop running windows XP. The Processor cooling fan won't come on. I got it to work one time by doing a disk cleanup but now it is back to not working. It let me know the fan is okay but I don't know what else to check. Is it a Registry problem or what and how do I go about trouble shooting it. Thankyou for anyones help. rogerbrener@yahoo.com