how to quiet a noisy computer

The best thing you can do is to change the CPU cooler, change computer case and power supply with some silent ones ... And that should reduce your computer noise

actually there is several ways to reduce the computer noise, the easiest way it close your case (if your case is open), and you could also change your fan to quiet model, ot reduce the fan speed (it will cut the noise a lot), or if you using the processor and fan processor that allready capable of speed step you should turn the feature on, example using coolnquiet on amd64 based processor, it very very decrease the noise. (I allready try it my self) hape can help a little