I have the same problem and I called (Sprint) and they told me to restore it so I try and restore it again and not I cant even use my iphone 4s anymore I was looking at other sites and saw a boot up after an update and it gave this person an error after they did an update but one of the code lines in the boot up gave an error after trying to update the baseband soo its apple's problem with their update from itunes! Btw Sorry i cant help like I said im haveing the same problem....
Hi i had faced the similar issue but i could resolve easily. I followed the following steps:
1. Restarted my laptop.
2. Restarted my iphone
Re-connected my iphone to laptop, opened iTunes and iTunes automatically asked for "Restore from Backup".
I selected the option and it worked.
You can also refer to following urls:
2. Check for Resolution step and click the line "how to restart your ios device"
Hope it helps.