What constitutes a proof of purchase? The receipt only? I bought a MPB from the Apple Store 2 weeks ago, which I plan to give to my sister in Europe. However I just realized if she needs to have it serviced (within the 1st year period) they might ask her for the proof of purchase. Now, I am not sure if I even received a receipt with the laptop, or if I did I might have thrown it away. What should I do? Since the computer hasn't been registered yet, would it suffice if my sister registers it to her name when she gets it?