Hi guys, i just bought secondhand I phone 3G 8G. I just install i tunes to my pc and everything goes well with my i phone. suddenly the i tunes ask whether i want to upgrade from 3.1.2 to 3.1.3. I choose to upgrade, however when the process finish, i cannot log in to my i phone. when i connect the phone to the i tunes, it said that "The sim card inserted does not appear to be supported". and the display at the i phone just show the icon i tunes and usb cable. Anybody could help me because i really need to use this phone urgently....