I got yet another free Apple product the other day, it's an older powerbook, 800mhz G4. I have no idea what generation it is, but I think they were reffered to as "Titanium" Anyway, the HD is making some clicking noises, and I would like to get a 7200rpm replacement. The problem is that I have no idea where to look or what to look for. I have never bought a HD for a laptop, let alone for a Mac. Any suggestions?