I have a Samsung SGH-T639 and it is unlocked. I put in the new AT&T sim card in, but when I get to the main screen it just says search... forever. It's looking for the network, but it just can't see it. When I put in the original T-Mobile sim card it says, "no service." Which makes sense since I switched that service to my smart phone.

How do I activate the at&t card?


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