I have a 2-yr old Craftsman 1/2 hp Garage Door Opener. It stopped working a couple of days ago. First, the door would not open fully at a single press of button. Then it stopped responding completely to the in-wall button and remotes. I can move the door up and down manually. The motor buzzes and the chain moves when I hit the button. But the door does not move at all.

Any advice will be appreciated.