This just happened to me this morning. I updated iTunes to the latest version and rebooted. Still no joy. I then swapped the USB cable to a different port with iTunes running and then iTunes said that my phone was in recpvery mode. It then asked me if I wanted to recover the phone and I said yes.
It then restored the phone to factory settings, took about 5 minutes.
When the phone was restarted iTunes asked me if I wanted to restore or set up as a new iPhone. I chose Restore.
When restored my iPhone was at the latest version (5.1)
Try putting your handset in DFU mode.
- Plug your iPhone to your computer (don't worry if iTunes doesn't pick it up)
- Power OFF the device
- Press BOTH the Power and Home key at the same time for at least 10 secs
- Release ONLY the Power button (keep the Home key pressed)
- iTunes will have picked up your handset in Recovery Mode
- *Screen MUST still be black and not showing the iTunes USB logo* If so, repeat above.
- Now click Restore
You should see iTunes download (if not already) the lastest iOS firmware, you'll see the progress bar on the iPhone finally as it updates.
See how that goes.
It can take several goes to get the handset into DFU mode, the key is the iPhone screen is still OFF!
Yes, well, I have the same problem except that I'm on vacation in China with my son with the phone being our connection in case we lose each other. The problem occurred out of nowhere and I have no laptop to 'restore' it, thanks a lot Apple for extremely expensive, unreliable products. Big fan here.