Last week I bought a Macbook and a iphone 4s from a young lady that was moving to Singapore. I did my due diligence and went to the Verizon store and made sure that the iPhone was in fact hers. It was. The Macbook worked perfectly and I paid her. Both parties happy. Until today. I tried to upgrade and low and behold she didn't erase everything and the ability to upgrade are password protected. The only way to get a hold of her was the phone # she gave me and that was the iPhone before I re-registered it. Is there ANYWAY I can totally erase the disk and start over. I don't have much on it and I can back up what I do have. Help!