Samsung S5260 hard reset
Use this method to hard reset your Samsung S5260 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.
See also Samsung Star 3 reset
If you know the hard reset using buttons / keys, pls leave a comment. All comments are welcome! :)