Noisy Cpu?

You'll wonder why your CPU is giving a loud buzzing or humming sound.  Most likely those fan are getting too much dust in it and if you don't fix it, they will burn out and may damage your system.
All you need is the CPU power off, open the side panel and take that noisy fan out. Dust off those fan blades. Slowly peel off that label located on one side of the fan. some of this fan have a rubber like plug on top of it which is very easy to pull out.
If you have this kind of oil use for sewing machine that will be just fine.  Just one drop will do. Wait for the oil to sip in. and try to gently spin those fan blades until you will notice that fan will slowly spin smoothly. Put the plug back and stick that label back on top of it. Put it back to its original position, close that side panel and turn your CPU on.    Noise is gone!!!