Hard Reset SAMSUNG G900A Galaxy S5

First method:

1. Please power on your handset.
   
2. Then tap Menu -> Settings -> User and Backup -> Factory Data Reset.
3. Now you should to confirm all operations.
4. Finito!

Second method:

1. Remove and insert the battery.
2. Then press and hold 3 buttons: Volume Up + Home button + Power button.
   
3. Next if you see menu, release the holded buttons, and select option "wipe data/factory reset" using Volume buttons and confirm with Power button.
   
4. Now confirm operation "Yes -- delete all user data with Power button.
   
5. Select option "reboot system now".
   
6. Good job!

Third method:

1. Turn on your phone.
   
2. Now please type this code: *2767*3855#
3. Afterwards your cell phone will reset and reboots.

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