hi have had a few drives like this myself hope this helps.
1. look at lazer for dullness and clean it with alcohol based product and cotton ear bud.
2. check the dvd spinal for stickyness ie turn the black circle by hand if its not lose its fooked. and will give you the message your haveing.
3. wd40 on the motor that drives the disc, just a tiny bit thought so it spins up like new again i found on some older drives this fixed the issue first attempt.
lastly was the tray not closeing fully ie the tray was in but the disc section hadent engaged fully up after closeing i found regreaseing all the slides and then manually eject and close a few times soon fixed thats issue .
again this is just what i have tried in the past and had succes on in fixed open tray issues so like others in here have helped on things i knew nothing about i hope this helps you in repairing this error just a little quicker .
happy gameing all/