My iphone 3GS wont activate after i updated it to IOS 6.1?

So i bought a second hand iphone 3Gs and i updated it from 4.1 to 6.1 but now it wont activate i have no clue why and I would like to know what to do. So what do I do?

You need to have a carrier supported SIM card. I havent jailbroken a phone in 6 months but if you jailbreak and choose hacktivate, you'll be good to go. If you need help go to iphoneforums.net