ie: You press the call button (green phone) and it shuts down or other similar behavior?
This tip will save you a trip to the Nokia service center and perhaps money. Type this on your phone:
*#7370#
It’ll then ask for a password to do a “hardware reset” so type:
12345
NB: Upon doing this be prepared to lose some of your settings, most recent contacts, saved images, messages sent/received, etc!
Good luck!