Sounds like you need to unlock the phone; or buy a SIM card which is specific to the carrier to which your phone is attached.
------------------------------My current set up is: CPU: AMD Phenom II x6 1065t @ 4.0 ghz/1.5v CPU Cooler: Cooler Master V6 GT Mobo: Asus M5A99x EVO Ram: 8 Gigs RAM PSU: Cooler Master Silent ProM 850 GPU:2xCrossfireX Asus 6850 Case: HAF 912 Reply to bobusboy