OK, This has to be the strangest thing I have ever come accross. When I plugged the Optiplex into a KVM box and powered it up, I got thru the BIOS boot process, and was able to get into BIOS Setup. I checked it out on another of the same systems with the same problem, and got the same result. I am now able to load a new O/S.
I wonder if after I load the O/S, will it boot without the KVM?
I'll let you all know.