Failed to install: "Detect and mount CD-ROM" failed

["Stephen Turner" <s.r.e.turner@gmail.com>]

Trying to install etch from the netinst CD on a two-month old desktop machine.

Boot from CD, choose language and location, and then it fails to find
the CD drive:

 Detect and mount CD-ROM
 No common CD-ROM drive was detected.

I have previously installed on an even newer laptop from the same CD.

Any clues how to start diagnosing this?

Thanks,

--
Stephen Turner