Hi, we had exactly the same problem this morning. ***I*** ***haven't used this device for more than 4 years***, now it says ''NO DISC or UNSUPPORT''. Fortunately, after about 4 hours of searching for the problem, I've found it. There are two ways to solve this problem, both require opening the Yamaha (don't worry, it's pretty simple).
***(1) Unscrew the cover (about 8 screws).***
(2) After unscrewing, you will find roughly in the middle of the device the ***main train*** (where the CD is). There is a laser (transparent dot), ''if it is dusty then clean it.'' If it seems clean, then the problem is a ''stuck wheel that moves the cd and laser.''
(3) Unscrew this cover as well (4 screws), under it you will ***find*** the whole ***unit*** (that moves the cd and the laser), you will also ***find a gray wheel there***, move it so that the whole unit moves to the other side (of the cd track). Before screwing everything back in, I recommend trying it first. So plug it back into the socket (carefully, don't touch anything) and put the CD in there. ''Now it should work.''