I have a pro-form 415. I do not use the incline feature. Today when I started to use it, it was inclined up about 3 or 4 levels. The buttons to decline the slope do not work. When I hit start, the clock starts in seconds, but the treadmill does not move. I tried unplugging it and plugging it back in. No change. Should I buy a new motor? Will I need a new machine?