SAMSUNG I9100 Galaxy S II

Hard Reset SAMSUNG I9100 Galaxy S II

First Step:-

1. Remove battery, and put in after 12 seconds.
2. Press Volume up and Home button in the same time.
3. Holding Volume and Home button press Power button for 5 seconds.
4. you will see Recovery menu choose "wipe data/factory reset" using Power button to accept and Volume buttons.
5. Next accept option "Yes -- delete all user data".
6. After that confirm select option "reboot system now".
7. Finish.

Other method:-

1. Power on your phone is on.
2. Go in to Menu.
3. Choose Settings -> Privacy -> Factory Data Reset
4. select Reset Phone

Code method:-

1. Turn on phone.
2. Press *2767*3855# on Screen.
3. Turn off and turn on your mobile.. 
4. Done.