Hi all, I'm looking at a Macbook on eBay, and am seriously considering purchasing it. The seller included a picture of the UPC, so I know that the computer is eligible for the factory warranty on a new Macbook. My question is, if I take it to the Apple store to get fixed, what kind of documentation do they require at the Genius bar? Sales receipt? Serial number? If it's an Apple store sales receipt they want, would an eBay sales receipt be a substitute? Sorry for all the questions, its just that Apple warranty is kinda hazy on the details.