My wifes computer is a Dell Dimension 4550. Yesterday we noticed her cooling fan constantly runs and does not shut off. I have tried going into bios to check temp inside computer and option is not there in bios to do so. I opened computer up and cleaned it really well and it does not seem hot inside at all. Could someone give me some ideas. It has two fans inside. A real big one and small one and they both seem to be constantly running. Is this a problem we should worry about. Help and thanks so much.