Ohhhhhhh, please tell me you are all joking.
I have an n505, and this only started happening to me the other day. I've had the thing for less than 6 months - but didn't buy it brand new (refurbished to new condition).
I had 75 songs on one MD and I got sick of a couple, so I plugged the thing into my 'puter to delete and replace with others... and when I unplugged it and tried to play the new songs it told me the disc was blank. But OpenMG (piece of junk) showed me the tracks on the MD as I was recording them, so I assumed that it wasn't registering that there was a disc in there. I replaced the battery but I got the same blank message.
So this means my MD is stuffed?
Mate, my parents are going to kill me - I had a hard enough time convincing them that it was AUD$160 well spent. If that's the truth, Sony have lost a hell of a lot of business. I was about to convince a friend to buy a unit - not any more!