I'm sorry to hear that you're having this problem.
If you try holding down the FF button for 12 seconds, the until will reset. This may or may not fix it, but a reset is the best I can suggest at this point.
If not, it may have to be serviced.
Last night I was adjusting a cable on the back of the unit and leaning it slightly forward. At the same time, I closed the tray. Somehow the motor did not catch the tray, and now it will stay open at all times. It does play back discs and everything seems to be working, but it now thinks it's open, even if it's not. When I press open, it even pushes the tray further forward, and then returns it to it's open position when it closes. How can I fix this?