Hard Reset SAMSUNG G355H Galaxy Core II

First method:

1. At the beginning switch off the cell phone by pressing the Power button.
2. Afterwards press and hold together: Volume Up + Home button + Power button for a while.
3. Release held keys when the Samsung Logo appears on the screen
4. Then select from Recovery Mode menu "wipe data / factory reset" using Volume buttons to navigate and Power button to confirm.
   
5. Choose "Yes -- delete all user data" to confirm the whole operation.
6. After that select option "reboot system now".
7. Well done! The hard reset has just been performed.

Second method:

1. Start by turninng on the device.
2. From the Home Screen go to Menu and then to Settings.
3. Tap Backup & reset and then Factory Data Reset.
4. Afterwards find and select Reset device.
5. To confirm your choice select Erase everything.
6. That's all.

WARNING !
Hard Reset will erase all of your data
All described operations you are doing at your own risk.