I just recently bought a new 15" rMBP so I'm recycling my old 17" mbp via Apple's website. Now that I have everything backed up and transferred, I did a 7x erase of the 17" HDD. Once it was done I figured I needed to reinstall the OS. 1. Do you think reinstalling the OS is necessary? 2. If it is, how do I set it up without Registering the computer under my information? I'm using PowerOn as the recycle and credit service so if anyone has done this before please let me know.