I recently purchased a 2012 MacBook Pro from an individual on Craigslist. The computer is in excellent condition, with an existing hardware warranty that's good until February 2014. The previous owner removed his files from the 1TB hard drive, and then reformatted the drive prior to my ownership. It's becoming quite apparent that he he forgot to deauthorize the computer, using his Apple ID and password. Is there anyway I can disassociate with any previously-used Apple ID(s) and factory start fresh? Any help you can offer me will be GREATLY appreciated!