I got my Macbook Air about 3 weeks ago and love it. However after the first 2 weeks, one day I turned it on and it was making a loud grating, spinning noise. The noise could be equated to if you try to play a CD but it hasn't been secured in the CD player fully so its banging around. But of course I have no disc drive... So I stopped using it, tried turning it off and on again a couple of times over the next few days to no avail. I'm about to go back and demand a new one, but yesterday I turn it on and it's suddenly stopped making the noise. My question is, is this problem likely to return, and is it due to a defective laptop? Should I see about exchanging it while it's still brand new or just wait and see if it happens again?