Buttons wont work and Phone shuts off randomly

My Motorola Sliver L6 buttons have recently decided to stop working. I can boot the phone up but once the login has completed and when I reach my home screen if I push any of the buttons nothing happens and the phone will just shut off. If I wait for the screen to go off and the keypad to lock then I am not able to unlock the buttons because the keypad does not work. Sometimes the menu button will work. The phone still plays sounds and I still get incoming calls but can not answer because buttons don't work.