I have a 2.0 Ghz 20" iMac G5 (The ones right before the iSight iMac). I've been hearing this chirping noise coming out of my computer sometimes when it's either been on for a long time or something, I don't know. All I know is that it's driving me nuts! Does anyone know what is making that noise and how can I fix it? Is it covered under AppleCare?