Hi my name is ***** ***** to Just Answer. I am reviewing your question and will reply ASAP.
If the iPhone is not detected when connected to iTunes, try Recovery Mode.
While your device is connected, force restart it: Press and hold both the Sleep/Wake and Home button for at least 10 seconds, and don't release when you see the Apple logo. Keep holding until you see the recovery mode screen.
Now the iPhone should appear in iTunes, please choose to Restore it.
When it is finished restoring, set up as a new iPhone, don't recover from any backups.
Let me know if there are any problems or questions. Thanks in advance!