Hey guys, my classic MBP is about 11 months year old now, and I recently noticed this high pitched sound coming from it. After leaving it on for a night to encode videos into iPod format, I noticed that there's this irritating high-pitched whining noise that is present every now and then. Even more annoyingly, it seems to come on every time I get an Adium message. At first I thought it was the message alert sound setting it off, but it seems to happen even when my Mac is mute. When I boot the Mac, the boot sound is also accompanied by some noise. Any idea what is causing such a problem?