for LG E739 ultimate solution

  1. Before You start everything use your two fingers to tap the back and menu (spring Key) keys or pad
  2. Press and hold the Volume Down and Power keys.
  3. After 2 or more seconds phone powers on remove your hand from the power and the volume down keys
  4. Keep your two fingers on the back and menu (spring Key) pad
  5. watch the LG LOGO carefully it will blinked
  6. immediately you see the LG LOGO has blinked, remove your hand from the back and the menu (Spring Key) keys quickly
  7. Now Wait for your phone to Wiped out