My iphone is only a week old, and I was walking to a spot to get service and it suddenly shut down and showed me the little dim apple screen that's usually there at the beginning of a start up. It went to the brighter apple screen of the same thing, then stopped and started over. It gets to the same spot every time and just does it over and over again. Soft and hard reset haven't worked, and plugging it into the outlet or computer makes no difference. iTunes doesn't even really register it's plugged in. What should I do???