My new 15" PowerBook's 80 GB hard drive has been making some light clicks lately..not reading or writing, I can hear that noise over the clicking. It sounds like.....if you were to take a plain pencil tip over some fine grit sandpaper...only a little lighter. At least I think it's the hard drive, anyway. Is there a way to force the hard drive to spin down without waiting 15 minutes? I'd like to listen and see if it is indeed the drive.