is the laser sitting all the way over on the right hand side of the tray?
if so, you'll need to open the duo up and wind the mechanism back by hand. this seems to be a reoccuring problem with the original (black) duos especially when playing cdrs as opposed to real discs. It's pretty painless once you've found the right tool bit to open the console with.
if not, then i'm guessing your laser has had it. I believe a guy on these boards called d-lite has been helping other people source new drives, maybe try messaging him?
hope this is of some help and you get the little fella working again
R