My iPhone 3gs won't activate after I restored it?

My old iPhone 3gs said, when i plugged it into my laptop, that it wanted to be restored, when i did, and i got onto the iPhone, it came onto a screen where it wanted my regional and language details, then made me connect to my Wi-Fi, however, when it came to activating it, my laptop said it couldn't continue with the activation, and to try again later or contact customer support, i have tried several times, and i don't have a mac, so i can't ring apple support, any ideas? P. S i'm not brilliant with apple stuff, so if you have a solution, please dumb it down, thanks!

Could be locked to the original carrier.
you need the original sim that came with it.
or jailbreak it