How to restore iPhone's factory setting
- All your data (if not backup-ed on iTune) will be gone
- Connect the USB cord to your computer and open iTunes.
- Press and hold the Home and Power button to turn off the device.
- Press and continue to hold the Home button while you reconnect the USB cable to your iPhone. This will turn it back on.
- Continue to hold the Home button until an alert message in iTunes appears that an iPhone in recovery mode has been detected.
- Now that the iPhone is in recovery mode, you must restore the device.
- From iTunes, look under the “Summary” tab.
- Click on the “Restore” button within iTunes.