Hard Reset SAMSUNG S730M Galaxy Discover

First method:

1. When your phone is on, press middle button(similar to the arrow) -> the left button (similar to the book) and then tap System settings ➔ Back up & reset.
2. Then tap to Factory data reset.
   This action erases all data from your device except current system software and bundled applications, or SD card files such as music or photos.
3. Next tap Reset phone ➔ Erase everything.

Second method:

1. Power off your phone.
   
2. Then hold and press Volume Up + Power button until phone vibrate.
   
3. Next select option "wipe data/factory reset", and confirm that with Power button.
   
4. Now choose from the menu option "Yes -- delete all user data".
   
5. Select with Volume +/- option "reboot system now", and press the Power button to confirm that.
   

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