1. Turn off the device.
2. Press and hold the Volume Up and Home button,
then press and hold the Power key.
3. When the Samsung Galaxy Core Prime logo appear,
release ONLY the Power button.
4. When the android logo appear, release the Volume Up and Home button.
5. Use the Volume button to highlights 'wipe data / factory reset',
then press Power button to select.
6. Use the Volume button to highlights 'Yes -- delete all user data',
then press Power button to select.
7. Use the Volume button to highlights 'Reboot system now',
then press Power button to select.