It seems like almost anytime I do any CD ripping or batch converting in iTunes, at some point my Powerbook will make a very loud, sharp click. I would almost describe it as more of a snapping or popping sound than a click, even. It's definitely much louder than any normal hard drive activity. I'm a little bit concerned that it could be the hard drive dying, but the funny thing is that it doesn't even sound like it's coming from the hard drive. It sounds more like it is coming from the left-hand area of the keyboard. I haven't had any errors in ripping or encoding when the sound has occurred, either, which also makes me hopeful that it might not be the hard drive (although more worried that it could be something on the logic board). Does anyone have any ideas?