RIM BlackBerry 7250 "reset bell receiver" Questions

...reset the unit, and when she put the battery back in, you can't do anything with the unit. - You can scroll the menus, but not select them - You can hear the phone ring, but not answer it - You can ...

...bell ringing, but the phone itself fails to play the ringtone nor am I able to receive the call. The only way out is to do a soft-reset after which the phone is completely normal till I press the ...