Currently Being ModeratedDec 8, 2012 1:52 AM (in response to Kristenx2)
contect the carrier maybe the sim is damaged
or if the phone was jailbroken to sim unlock it then updating the ios version will relock it in which case you need to contact the carrier it was orgrinal locked to as how to get it unlocked
Currently Being ModeratedDec 8, 2012 3:12 AM (in response to Kristenx2)
Power off the phone and eject the microsim holder . Then push it back in and power on again. The phone should detect the SIM , unless the SIMcard is damaged.