Hard Reset SAMSUNG I9190 Galaxy S4 mini

First method:

1. Make sure, that your device is on.
2. Tap on Settings -> Back Up and Reset -> Factory Data Reset -> Reset Device -> Erase Everything.

Second method:

1. Turn your phone off.
   
2. Then press and hold Volume Up + Home button + Power buton, and wait until the logo appears, then release.
   
3. Now you can see recovery menu, where please use Volume buttons to nawigate to ”Wipe data/Factory reset” and confirm with Power button.
4. Next choose "yes", and confirm with Power button.
5. After this operation, select "reboot system now".

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