How to Hard-Reset the Samsung Galaxy S i9000

First method:

   1. From the main home screen, tap menu
   2. Tap Settings, then Privacy
   3. Tap Factory data reset
   4. Tap Reset phone
   5. Enter your password, then tap Yes to confirm

Second method:

   1. Turn the power off.
   2. Hold down the Volume Up, Power and Home (bottom center) buttons.
   3. When the "Galaxy S GT-i9000" startup screen show, release all the buttons.
   4. Use the Volume Up/Down button to navigate to "wipe data/factory reset"
   5. Press the Home button to confirm.