I have had recent noise coming from my computer, the sound is a fan that is making a squealing noise. I know it is not my video card because it has been recently replaced when the computer was making the sound. It is also not my misc. fans because I've disconnected them to diagnose. So that leaves my processor fan or my PSU fan. Now today I had the computer power shut off all of a sudden and a burning smell came from my computer. I disconnected it and left it for a while, then quickly plugged it in with the side door open to see if the fans were spinning. The processor fan is spinning, but the PSU one is not. I can't tell where the noise is coming from so just wondering if the PSU fan is suppose to spin all the time. That way I can replace the correct part. I don't have any replacement parts so I really need some help. Thanks in advance.