Recently I've had a PC start to make an unbearably loud ringing, squealing, or screeching type sound. It is NOT a beep code; I know the difference. It's an annoying high pitched squeal, here's a video I found where a PC makes a similar sound, it's like this but much louder: http://youtu.be/Tn6i4-Atg5k
It started when I noticed a loud rattling/clicking type sound coming from the PC so I opened it up, cleaned it out, and tightened up all the screws in case something was slightly loose. I suspect it may be the PSU; initial noise was coming from the back of the PC. Anyway that did resolve the rattling/clicking noise but that's when the squealing noise started. Is there a way to fix it or do I need to replace something?