Thank you very much for the advice Titan8990.
The problem with Dell Dimension computers is that the fan is completely encased in plastic on the inside of the computer tower, and from the outside I can see it only through a metal grate, so I would have no way of preventing it from spinning.
Thanks for letting me know about speedfan. For some reason I had been under the (mistaken) impression that the hard-drive temperature was the main thing to look out for, mainly because it was usually quite higher than the CPU temp on my laptop before I got a notebook cooler.
edit: In case anyone out there is wondering how to remove the plastic case from a Dell Dimension fan, lift the side further from the back of the computer case up...the other side has hinges so the cover can't come off completely, but makes keeping the fan from spinning while cleaning a lot easier. One would think this would be easy, but the case sits pretty firmly in place and at first seemed like it couldn't be lifted.
Edited by CelestialTeardrop, 22 May 2007 - 08:25 PM.