To restore iPhone to factory
settings, follow these steps:
1. Connect your iPhone to the computer and open iTunes.
2. Make sure your iPhone is selected from the left menu in iTunes.
3. Click the “Restore” button in the center of the iTunes Summary tab.
4. You can choose to Back Up the contents of your iPhone to the computer.
5. iTunes will ask if you're ready to Restore the iPhone, this will wipe all of your data and settings from the device. Click Restore.
6. iTunes will download, prepare and restore the software on your iPhone. Do not unplug the iPhone from the computer during this process!
7. When finished, iTunes will ask if you want to restore from backup. Choose "Set up as a new iPhone" to start fresh with factory settings.
8. Enter a name for your iPhone and the process is complete.