I'm getting a strange cyclic noise from my pc...

[LeonRa]

I have a strange cyclic noise coming from my pc and i can't find out what is the problem.I have already stopped all the fans and unpluged the hdd's and it still persist. It's driving me crazy ( I've trown a lot of money to make it silent).
Could it be the motherboard or the PSU ( but not the fan of the PSU i stopped it too)?
Any help will be apreciated.

 

[mlj]

can you explain the noise better

 

[terror112]

The power supply fan and the disk drives are the only things that could make noise in your case so you should check them out.