First method :-
- At the very beginning turn off the cell phone by holding the Power button.
- Afterwards in the next step hold down the Power key until the device vibrates.
- Then press and hold together Volume Down + Volume Up button for a couple of seconds.
- Release held keys when the Recovery Mode appears on the screen.
- In the next step press Volume Down to highlight "wipe data/factory reset", and then push the Power button to confirm.
- Select "Yes--delete all user data". Use Volume Down button to scroll and Power key to select.
- To restart the phone, select "reboot system now".
- Success! The hard reset is done!
Second method :-
- Turn on the phone by using the Power button.
- Go to Settings and then to Backup & Reset.
- Tap Factory data reset.
- Choose Reset phone and select Erase everything.
- Well done! Your phone should restart.