I recently bought a second hand MBP. When I turn it on, it's at the start up page. I click "Re-install Mountain Lion". After a few steps, it asks for the seller's apple ID. Although I could ring him and ask for it 1. I don't want his apple ID to be in my purchased Macbook anyway. 2. I don't want to keep ringing him for his password again and again. Is it possible for me to go the app store, purchase Mountain OS X Lion with MY apple ID, and then use that ID to log in for the re-install? Or will it reject it because the OS X Lion that HE purchased and put into the Macbook is still there? Sorry, I'm bad at explaining things. It's just super frustrating.