- Press Power button, until your phone is off.
- Next hold and press Volume Up + Volume Down + Power button until you see menu with 2 options.
- From this menu choose option Recovery Mode.
* Press Volume Up to enter this mode.
- If you see Android logo on your screen, then press Power button.
- Navigate to option "wipe data/factory reset" using Volume buttons to scroll, and Menu key + Back key to confirm.
- Then accept this: "Yes -- delete all user data" with holding for few seconds Menu key + Back key.
- After that confirm option "reboot".
- That's all.
Hard Reset will erase all of your data
All described operations you are doing at your own risk.