In order to hard reset a Samsung Mesmerize i500, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Samsung Mesmerize i500 device will be brought back to the default configuration of a brand new device.
1. Turn off the device.
2. Press'n'hold Volume Up and Down + Power buttons. Release Power button when Samsung logo appears.
3. Release rest of the buttons when Recovery Mode starts.
4. Use Volume buttons and Power/Home button to select Wipe data/factory reset.
5. Afterwards, select Yes...
6. ... then Reboot.
7. Done! Your phone will now reset and restart.