Begin by switching off the cell phone, by using the Power button.
Then press and hold together the Volume Up and Power key for a few seconds.
You can release held keys when you see an Android icon.
Then use Volume buttons to select "wipe data/factory reset" and tap the Power button to confirmnow".
Afterwards choose "yes" from the menu, and accept it with Power button. When a Recovery Mode appears again on the screen accept option "reboot system
