After I had missed a few calls, I went to the volume control page to assure that ring tone volume was turned up. There are green lines with slider buttons underneath "media volume" and "alarm volume" but not under "ring volume". On the page that lists available ring tones, none of them sound the tone when clicked on. Vibrate no longer works. I tried shutting the phone down and rebooting. Resetting it might work, but I am not sure how to back up, then retrieve, my contact list and would hate to lose it.