What exactly happens when you click on restore in iTunes? Error message?
Restore loop (being prompted to restore again after a restore successfully completes)
Troubleshoot your USB connection. If the issue persists, out-of-date or incorrectly configured third-party security software may be causing this issue. Please follow Troubleshooting security software issues. .
Next try placing in DFU mode and then restoring.
Last, try restoring on another computer.