Ive had this problem and it was a jammed cd.
Fixed now and loads 6 cd's.
Resulted in hitting it but it worked.
If you either mute the volume or turn it down you hear it trying to load something and a bit of clicking noises.
Hold the "load" button down till it says "load all" while it tries to load, hit it just above the cd slot, on either side of the hazard button, the shock may jump the "jammed cd" into place.
If so it will say "insert cd", have 6 cds ready to load.
Put the cds in when it tells you to, and where there might be a jammed cd, it will skip telling you to insert one and then loads the jammed cd into the space, then run through the cds to see if they play.
Then after checking that, hold down the eject button till it says eject all, then you should have 6 cds and one might not be what you inserted in, thus being the "jammed cd" this has fixed the problem for my cd player.
But resulting to violence to fix things doesnt always work, but it did this time.
I hope this way slightly helps you with fixing it.
Rob
Rob, January 2009