reset Samsung i550 Symbian hard reset
Sorry it may NOT work. See comments and confirm.
Samsung i550 Factory settings
Reset settings to their factory defaults. You must enter the lock code to reset the device. After entering the code, the device will restart.
Default lock code for Samsung i550: 00000000
An application is frozen (will not respond)
1. Press and hold [lower top left App key] to open the application list.
2. Scroll to the application that is frozen and press [C] and then <Yes>.
3. Launch the application again.
Use this method to hard reset your Samsung i550 Symbian 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.