some of the Denons from that period sound excellent. It's worth a shot.
First, turn the unit over and see if there is a locking mechanism on the bottom for the laser, it could be locked.
If not, Open the cover and then open the drawer. Look at the CD mechanism.
Put in a CD and push play. does the CD spin? If so, the laser is probably good.
See comments about cleaning.
If not, try turning the CD with your finger right after the drawer closes. Does it spin? If so the disc motor is bad. If not, the laser is probably bad.
Does it have a gear to move the laser back and forth? If so, look at the laser. there will be a small pc board on the laser assembly with a sticker on it with a part number, Either KSS150 or KSS152. which is it?
If there is no gear, turn the power off and gently try to move the pickup back and forth. It should move with very little effort. If it moves and locks up or snags the two polished metal rails the laser slides on must be meticulously cleaned with alcohol and a q tip until nothing comes off. Then you need to apply a very thin layer of Lubriplate to each rail and slide the laser back and forth to spread the lubricant. that may fix it.