Unfortunately, You will have to restore your iPhone 4. This will remove all settings, Accounts, photos, music, contacts. ***Everything will be erased.***
=== ***Before You Begin***: ===
* Ensure you have the latest version of ***iTunes*** installed on your computer.
=== ***Steps to Restore Your iPhone 4***: ===
# ***Connect your iPhone 4 to the computer*** using a USB cable.
# ***Open iTunes*** on your computer.
# ***Put the iPhone into Recovery Mode (if needed)***:
** Turn off the iPhone.
** Press and hold the ***Home button*** while connecting it to your computer.
** Keep holding the Home button until you see the ***iTunes logo and cable icon*** on the screen.
# iTunes will detect your iPhone in ***Recovery Mode***.
# Click ***Restore iPhone*** in iTunes.
# Confirm by clicking ***Restore*** again. iTunes will download and install the latest compatible iOS version.
# Wait for the process to complete. Your iPhone will restart with the factory settings.
# Follow the on-screen setup instructions to set up your iPhone as new or restore from a backup.
Happy iFixing! :3