I was playing Tony Hawk's Pro Skater today, and when I turned off the sound to talk to someone, I noticed that my iBook's fan was making a sound sort of like a race car off the line - the fan was revving up and then cutting out, and revving up again, then cutting out, repeatedly. It only managed to get going at the longest for about 3 seconds. Is my fan dying? I'm worried that my computer will overheat without it, and the revving sound is *really* annoying. What do I do if it is dying - replace it myself or take it in (I'm out of warranty, and I've heard that iBooks are not that easy to take apart)? Any ideas at how much it would cost to fix? Arg! I'm quite at a loss here. Thanks!