Hard Reset SAMSUNG i515 Galaxy Nexus

First method:

1. Turn on your device.
   
2. Now goto Settings -> User and Backup -> Factory Data Reset.
3. Confirm all information on your screen.
4. Done!

Second method:

1. Switch off the cell phone.
   
2. Then hold and press 3 keys: Volume Up + Volume Down + Power button.
   
3. Next if you see menu, then release holded buttons.
4. Now search option "Recovery mode" using Volume buttons, and confim with Power button.
5. Afterwards you will see Android man with red triangle -> press Volume Up + Power button.
   
6. If you are in Recovery mode, then select option "wipe data/factory reset" using Volume Down button, and confirm with Power button.
   
7. Choose "Yes -- delete all user data" form the menu, and confirm with Power button.
   
8. After that select "reboot system now".
   

Third method:

1. Power on the phone.
   
2. Next just type thid secret code: *2767*3855#
3. That number code will force format on device.

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