Here is the reply from Dell:
I am sorry, but I can't find a replacement drive for this machine. It says on the service tag "return to depot repair only", I guess on the 1000 the cdrom is integrated into the system therefore it can't be sold separately. You will have to call tech support to set up an out of warranty repair. 800-www-dell, ext 7226586
The drive in this unit is almost identical to the drives in the GX280 small form factor optiplexes. I was able to take a drive out of an optiplex and put it inside the 1000. It was immediatly detected.
To install: remove the two optical drive screws on the bottom of the laptop. Eject the drive. Pull it out. Remove the two mounting brackets.
Then repeat in reverse with the new drive.