Sony plasma model PFM42V1 just clicks and buzzes

The customer got this set used about one year ago. He said that for the first four months it worked fine. For six months after that it still worked fine but he says that he was aware of a "humming" noise coming the right rear of the set (looking from behind). Now when you plug it in the red front panel standby light comes on and when power up is attempted the set clicks and the green light comes on and then a few seconds later there is a buuzzing noise that comes from the right rear area of the set. It does not power up though. This is my first plasma so any assistance anyone might offer would be most sincerely appreciated. Thanks, Lenny Stein, Barlen Electronics.