I am currently contemplating whether or not I should bid in an online auction on a 15" powerbook G4 1.67 GHz. I am quite sure that the seller is honest, however he doesn't have the original receipt for the powerbook and doesn't think it is still covered by Apple's one-year warranty. I asked him if he would be able to send me the serial number of the powerbook and he said he would later this week. I read on the forums that you should be able to use Apple's warranty (even without the receipt) so long as the previous owner agrees to transfer the registration to your name or has not yet registered the product. Is there any way I could check whether or not the powerbook is already registered with Apple. It would be great to buy a relatively new powerbook at a great price and get the warranty the powerbook is still entitled to.