Hey everyone, I'm seeking out some much valued help. I have a 27" Quad Core iMac that I purchased in the Fall of last year. It's worked great for me, but in January it started making an annoying, constant "chirping/buzzing" noise that increased when I would turn up the screen's brightness. It got so bad that I took it to the Genius Bar to get looked at. I was told the noise was due to a "faulty hard drive" so it was replaced. A few weeks after getting the computer back, the noise has returned and I fear it will only get worse. Does anyone have a clue as to what is going on with this thing? Thanks to whoever can lend some insight on this matter!