In My Computer The Cpu Fan Is Making So Much Of Noise That I Get Irritated To Work.I Changed The Smps And Fan Also. But Still The Sound Continues.what To Do?

Edit: Post moved to own thread. Incorrectly piggybacked on someone else's thread-Scott<>

Of course a fan starts noisily at the startup of a computer but is the fan still noisy after the startup?
The problems could be(listed by priority):
1.)The fan itself
-The fan could be defective but since you bought another one this case could either be rare or a coincidence. Also check if the fan bumps into anything or if it is not placed in properly. If not--
2.)It is a faulty power supply
-A noisy fan(usually CPU fan) also indicates a defective, damaged power supply. Try and be careful and once you smell anything burning(smoke) turn off your System Unit immediately.