Reset your Android in Recovery Mode -

To boot into Recovery Mode, make sure the device is powered off, then follow these instructions:

  1. Hold the Volume Up & Power buttons simultaneously (for Samsung Galaxy devices, hold Volume Up + Home + Power)
  2. Hold the button combination until you see the word Start (on stock Android). Samsung devices will load straight into recovery - release buttons when you see the Android logo.
  3. Use the volume buttons to scroll to 'Recovery' & press the Power button to select it.
  4. If you see 'No Command', hold the Power button & press the Volume Up button once.
  5. Use Volume Down to scroll down to 'Wipe Data/Factory Reset' & press the Power button to select it.
  6. Select Yes the same way.