OK, I promise that this is the LAST post on this subject.

As mentioned, I created a PuppyLinux installation and found that although the DVD drive showed up in the bios hardware list and was listed in the Linux systems info, when I installed a DVD and tried to access the drive, it would not function. The activity light would flash briefly but nothing more. Remember, this is the same drive that just created the new installation! I then downloaded 12.04 and burned a CD (rather than DVD as I had done earlier) which, when installed in the CD drive, worked as it should and allowed a normal installation. I'm happy to have found a solution but still not sure of the drive failure mode. This is like watching close-up magic, don't believe what you see happening!