Computer Noise

Not totally true. Sometimes the bits going into the bucket can create a lot of noise.

It might be the same reasons that transformers hum. See http://cr4.globalspec.com/thread/58345/Transformer-Humming.

LOL Electrons going around a corner, that's so funny.

Likely most of the audible noise from your computer is from a fan that has a failing bearing. In a desktop computer there are frequently three fans that might be your culprit, one in the power supply, one that cools the CPU heatsink and one that cools the video card processor. The power supply and CPU fans can easily be replaced with a new fan. The video card fan though is often a custom design that cannot be easily replaced. If this is the source, you will likely be happier just replacing the whole card.

The noise of which I speak is not fan noise.

It is more like little wizards using their abacus's (abaci?).

Whether or not it is just my very old and obsolete desktop, I don't know. But there is some random, rattle-like (at some level) noise.

Clicking sound could be the hard drive.

It is more like little wizards using their abacus's (abaci?).

You have hit the problem on the nail. Then why are you confusing people with all those technical jargons like electrons, corners, wires et al?

You mus be aware that there are several wizards inside any computer, less numbers when it is old one and more when it is newer model.

We have been taught in our younger days (before advent and proliferation of the TV) that there are real tiny people inside the radio who talk when we switch the set on (that is the signal to get up, and start talking. Otherwise they sleep inside the dark closed box. The time taken for them to get up is the delay that one observes between switching on and the starting of talks - people mistake it as the time taken for the valves to warm up)

In the TVs they have projectors with them too, and may be some film reels (that's why you keep on seeing the same movies again and again or even the news are with same pictures, with a bit of rephrasing)

Of course the computer is a bit of different ball game, there you need abacus too with the people trained in using these (of course some times they do make mistake - but then you would never know when they committed one would you?)

The main problem with you is

a) being old model, number of wizards are less, so they have too much leg space and must be kicking around or may be they are playing soccer in it.

b) Being old, may be their (wizards') bones have started rattling.

Solution- replace with new model- there they would be so jam packed that they would neither be able to play nor they would have enough space to even shake a finger, forget about bone rattling.

Of course the mistakes would be higher, but then you wouldn't know would you?

Well, that sure meets the Ed Weldon criterion: If it makes me laugh, it's a GA!

I'm pretty sure I have a gigantic (and perhaps rabid) dust bunny in my ancient desktop. I'm almost afraid to look, lest I get bitten. So far the weird noises are only intermittent.

I hope the MTBF of the fan is ≥ ~ 60,000 hours....

The only parts that should be moving are the fans. The transformers tend to be torroidal cores, so you probably do not have transformer lamination noise. Thus, take the fan idea and expand upon it. The fans probably have poor quality sleeve bearings that are both worn and partially dry. Thus, in addition to the blades cutting the air you have all sorts of wobble of the sleeve bearings. You can get some noise from them being out of round. You also get some noise from them running "end to end" from one mechanical stop in the fan assembly to the other end. Add to this the fans vibrating the box and all the single and bundles of wires inside it. Add in some hardware that might be loose and sheetmetal parts that don't fit as tight as they should. Put it all together and and you can either start working on your PHD paper or give up and just call it all "fan noise".

When I put a computer together I usually have one cable tie from a wiring harness that somehow ends up hitting a fan blade from time to time. I don't know how, after all these years, I still end up creating this problem. It causes random noises from time to time and can be confusing.

No hard drives in you computers? The disc spins, head moves back and forth