I tried to upgrade to ios4. The upgrade failed so I restored it back to the factory settings. However when iTunes searches for the phone I get this message: The iPhone you connected is not recognized and cannot be activated for service. I've spent an entire day at the AT&T store and on the phone with Apple and AT&T tech support. No one can fix it; they are sending me a new one--but it will take 2 weeks because of a shortage of 3GS phones. I'm using Win 7 64 bit. I also tried it on my XP computer, but the same thing happens. HELP!!!