Check your system for the following conditions:
1) Ensure that your CD-ROM drive is turned on and plugged into an live
electrical outlet.
2) Ensure the CD-ROM drive is properly connected to your Macintosh computer's
SCSI port (consult your CD-ROM drive's manual for instruction).
3) Ensure the CD-ROM drive's SCSI ID number does not conflict with another
SCSI device's ID number (consult your CD-ROM drive's manual for further
information).
4) Ensure all CD-ROM drivers are installed.
5) Turn on your CD-ROM drive before your turn on your Macintosh. If your
CD-ROM drive is already turned on, restart your Macintosh.
6) Use another CD-ROM disc. This will narrow down the problem to either the
your system set-up or your CD-ROM disc.