1. Turn off your Samsung
Galaxy S3 I9300.
2. Enter your phone
into Recovery mode by Press and Hold “Volume
Up + Home + Power key” until phone vibrate.
3. Wait until
Android Logo appear.
4. Select “Wipe data / Factory Reset” using volume
key and power button.
5. Select “Yes – delete all user data”.
6. And select “Reboot system now”.
7. Done!
8. Wait until your
phone boot.