I've had that problem a couple of times. The only thing that would work is a system restore.

I have a lite-on ltr 24102b cdrw. I've also had the problem with a lite-on ltr 16something.
I can't seem to find the drivers for them... only the firmware...

I also had that problem when uninstalling roxio, the cdrom couldn't be found. I had to reinstall roxio to get the drivers back. I endedup putting a regualr cdrom in there, and using the cdrw somewhere else.

What kind of cdrom is it?

Have you looked for the drivers and manually tried to install the cdrom?