Try this: Press “0 + 4-way navigation key UP + Power” screen will ask (1) formate and reboot.(2) Exit.
Use this method to hard reset your Samsung i200 phone: Enter *2767*3855#. Warning! All your data including contacts, messages etc. will be lost! Copy all your necessary data/Contacts/Messages etc. to SIM or make backup to your PC before full reset! Take out SIM card before full reset.
If you know the hard reset using buttons / keys, pls leave a comment. All comments are welcome! :)