My power supply fan starts to get noisy, I already thoroughly cleaned it but it is still noisy. Is there a way to replace the fan? Thank you, Jun

I've replaced many bad fans in psu's in the past. I usually scavenge the fan from an old psu
( a good reason for keeping old computers around ).Heat is what limits the life of electronic components.I've even added heat sinks and fans to new electronics such as my lcd tv (I installed 2 cooling fans).
While you have your psu apart you should take a look at the electrolytic capacitors. I've found bad caps to be at fault in psu's, motherboards, video cards, tv's, dvd players, even door entry systems.
The signs to look for are bulging or leaking (I had one explode in a video card). It's a good idea to replace all the caps if you find any bad ones. Radio shack can supply most of your needs.

Jun,

DON'T EVER REPLACE A NOISY PSU FAN -- replace the power supply. I worked as a component-level repair technician for 10 years (i.e., don't replace the board, determine which part(s) are bad and repair it).

The "weakest link" in a PSU is anything MECHANICAL, i.e., the fan. The mechanical fan will become noisy way before any electrical problems start.

If you DO replace the fan, you have removed "the weakest link". The NEXT weakest link is ANY voltage regulator. ONE of them will eventually get "flaky". When that happens, the supply sends too much or too little (or sometimes too much, other times too little) voltage to parts of the circuit. That will cause erratic behavior in the computer--lockups, crashes, mysterious self-rebooting, disk read failures, and hundreds of other possible "computer gremlins" behavior.

The "flaky" supply can cause ANY KIND of damage. It WON'T be an "instant failure". It could, for instance, trash the memory or the processor or the motherboard, any of which could cost a lot to replace. It could also trash your data or the hard disk itself.

When the fan gets noisy, replace the PSU. It's just not worth the risk. You don't have to run out when it gets just a LITTLE noisier. Like anything mechanical, the noise will increase over time. When it gets too annoying, that's when to replace it. It will still be WAY before any voltage regulator starts having problems.

If the fan is in the inside of the power supply, no it can not be purchased separately