said by Happyrat6:
Your problem is either a misconfigured bootup sequence in your CMOS SETUP or a loose drive cable and/or misconfigured drive jumpers.
The boot sequence would have little to do with complete lack of detection.
Other possibilities:
If the CD-ROM is located on the secondary channel, you may have the secondary channel disabled in the bios.
OR:
One of the wires in the cable could have over heated and severed. It has happened. Hence, cable gone bad. Test by replacing with known good cable.
OR:
The CD-ROMs controller is bad. Test by replacing with known good drive.
