1. First Turn off the Phone
2. Than keep Press and hold the Power button +Volume Up top + Home button together, until recovery booting appears
If the Android recovery screen doesn't display, you should do 1 and 2 steps again correctly
3. From the Android system recovery screen, select wipe data/factory reset.
Use the volume up/down keys to highlight and the power button to select.
4. Select Yes -- delete all user data.
Allow several seconds for the factory data reset to complete.
5. Select reboot system now.
Allow several minutes for the reboot process to complete.