cpu makes weird noise

[Bluedot]

my desktop is around 2 years old and runs quite smooth. however, recently, i've been noticing a weird noise coming from inside the box. i initially thought it was the processor fan getting clogged due to dust so i cleaned it. but the noise did not subside. a few days later the noise subsided completely and i forgot all about it. but it has started again. and what's weird about it is that it happens only during the first boot of the day. after i shut it down, cut the power and then restart, it subsides. it happens when i boot up my desktop after a long gap. need help with this.

[hal9000]

Have you checked all the other fans in the system including the PSU? Once it 's been running for a few minutes from cold, any fan making noise will often die down.

[Bearcat]

The cooler fan on the cpu in my old PC will ocasionally do the same thing. I have thought about replacing it, but since the noise always fades and the fan gets the job done, I just left it as is. Also, one of the case fans in my new PC makes noise once in a while. It is one of those minor irriatations that I just live with, because I'm too cheap to replace the fans.