If they read on other machines besides yours it might be a ASPI layer problem with the affected machine or some other driver or softeware conflict. I believe Nero will use it's own layer if the adaptec 4.60 or higher is not installed. it might also just be a dead drive as the pickups and other parts can get dirty or just go bad over time.
I know EAC and some other programs need a funtioning ASPI layer to read audio cd's, I had that problem with my XP install becuase it doesn't include it on install. I had to get ForceASPI that can be found with a search, or try the adaptec site, to get one installed then EAC worked fine.
I also had a LiteOn 166 dvd drive just slowly die on me, wouldn't read anything in the end so I replaced it with another new one and all is good again.