The chipset fan on the motherboard in my home theater PC started to make ridiculous noise, really within the first month of building it. Annoyed, I bought a little heatsink today to replace it. At $10 at CompUSA, it was probably a rip-off, but it solved the problem and now there's one less fan making noise (not to mention grinding noise). I'm thinking about getting another one for my desktop machine, which has the same motherboard. It's a really loud fan.
(the blue heatsink is the replacement, the little Abit fan is what was grinding)
Our TiVo was making a grinding noise about a year after we got it and the damned thing drove me crazy. Gordon just shrugged and said "it's a hard drive, what do you expect?" But it didn't make the noise when we first got it.
Besides, Gordon is so used to the hum of computers, synthesizers, etc, I'm not surprised he didn't hear it.