This might just help someone. My CD changer (6 disc in the boot) would not work. The display screen only showed "disc not found" or "no disc". After trawling many forums and finding the same symptom, I removed it and stripped it down. Following, as best I could, the suggested remedies, then re-assembling and re-fit in the car, it still would not work; exactly the same message coming up on the screen.
Removed and stripped it again. This time I moved the CD selector tray to pick the end disc; I then spun a cog wheel to bring the selected disc to the play position and re-assembled all and refitted in the car. It worked! Can't expalin why but it might help someone.
2002 X-Type SE 2.1L automatic