I got my 12" Powerbook 1.5 Ghz brand new about a month ago. For the last week or so it seems like the hard drive is making a whirring noise that sounds like a quiter fan. I don't think it's the fan because when the fan comes on, it's much louder, and this noise is present no matter how cool the computer is. I remember it being completely silent a couple weeks ago. Does anyone know if this is normal or should I be concerned ?