Power off mobile and remove battery and insert again.
Press and hold Volume Up + Volume Down and Power buttons together.
When screen show with no command press power button one time.
Two options will appear
Recovery Mode: Volume Up
Factory Mode : Volume Down
Press Volume up to enter recovery mode.
Select Wipe data/ factory reset and tap option key as shown in picture below.
Select with volume keys Yes -- delete all user data and tap option as shown above.
when format complete reboot mobile to complete the method.