IPHONE 3GS Problems. Updated to IOS6 then says There are just a few more steps to take. Press Continue. Once pressed it says connect to itunes. So plugged the cable in and it does nothing and stays on that screen. How can he fix it?

Hi, My friend has just updated there 3GS to IOS6 and once it's done, 2 screens appear. first one says, Update complete, there are just a few more steps to take. Press continue and another screen comes up with the itunes symbol and the cable and says connect to itunes. Once plugged in, on itunes it reconises the phone and has the loading symbol up, but it doesn't loads anything and can't press anything. Anyone know why and how to resolve this?