I'm pretty sure the problems we're having with a white MacBook are due to hard drive problems, but I thought I'd get a second opinion: computer was dropped on a hard floor started making whirring noises and would occasionally lock up or suffer long periods of the spinning wheel Disk Utility check, after booting up from the CD, cam back with no errors decided to wipe it and reinstall anyway Snow Leopard got stuck halfway through installing, so rebooted. Installation then carried on no problems. still suffering periods of the spinning wheel - it 'shudders' sometimes, rather than spinning smoothly. There have also been a couple of lockups. Any other ideas apart from a hard drive issue, before I buy a new one to install?