reset your samsung 5603
The only way to do that would be to perform a master reset. A master reset changes the phone settings back to the factory default. This process will erase all downloaded settings, contacts, and downloaded applications (ringtones, wallpapers, graphics, etc). A master reset cannot be undone. Enter *2767*3855# from the standby screen. (You may need to remove the SIM before it will allow you to type the code in).
*try it your own risk