How to silence my computer?

Drastic options for reducing noise include placing your computer in a “machine room” and using mouse/keyboard/monitor extender cables, or buying a special rack enclosure designed to house, quiet, and cool PCs. However, you can often reduce noise levels sufficiently with a thorough analysis and treatment of computer itself. To turn your roaring beastie into a silent computer requires minimizing heat build-up, choosing the quietest cooling methods possible, then using appropriate acoustical treatment.

Here is a site full of good advices on this subject:

http://www.quietpcusa.com/articles/how_to_silence_a_computer.html

http://fredrik.hubbe.net/silence/how.html

http://www.endpcnoise.com/ 

There are a few subtle options you can look into. This happened to me awhile back and I managed to work out a system that lowered the noise level tremendously. Before you can fix a problem you have to acknowledge the source. So your homework is to discover exactly what fan(s) is/are causing the cacophony. When you track those down there are few things to consider: Fans--usually--use a series of ball bearings between the blade and motor to keep friction down while the fan spins, that's why you don't have to oil your house fan. Occasionally with age some part of the motor or the blade will get damaged and, guess what, the bearings now have the opportunity to vibrate and cause much noise. This means that your internal fan is shot and you need a new one. Remember, some power supplies have fans built into them and repairing a power supply is extremely dangerous so you may have to buy a new one. When a fan is affixed to the side of a case it is usually done so with screws or bolts. This can mean two things: either the screws are on way to tight and warp the case over time or the screws aren't on tight enough and there's "wiggle" room between the fan and the chassis. In either case the fan manages to gain more "wiggle" room after x months and this time the entire fan is vibrating against the case. This can be fixed with rubber stoppers (usually called dampening kits) between the case and fan to cut down on the vibrations. OK, now that that is over I'm going to talk cash. Unfortunately for your wallet and fortunately for the resellers there is a strong correlation between fan quality and price. Remember those ball bearings from before? They are very quantative in that you have cheap bearings and you have quality bearings. If you are really looking to cut down on the noise invest the cash in a more expensive fan with a low dB (20-30 range) and better quality bearings. It will last longer, keep you computer cooler, and be softer. You know, you could always skip all of that open your chassis, unplug the fans and stick a quite industrial fan on the side and walk away. Good luck.

Hey, i had the same problem for the past 6 months my computer sounded as if it was going to take off. but yesterday my boyfriend and i took it apart and found that the fan's were clogged with an unreal amount of dust so we took them a part and cleaned every spec of dust off and now you wouldn't even know it was there that is how quiet it is. The problem was that the fan was to clogged to cool so it was working on overtime all the time. I'm lucky my computer didn't take off into flight.