Harry:

I want to thank you for hanging in there with me.
I woke up this morning with a clearer head and realized
it was a simple matter to reverse the roles of the two
computers I've been using in the test; that gave me a
chance to test two NICs on the "other" computer.

Bingo! You were correct in suspecting the card. Both
cards on the second computer, a VIA VT6105 (D-LINK) and
an Accton SMC2-1211TX could be (individually) brought
up to running. Ping and other commands working.

Thanks again for your help, I'll stop banging my head
on the wall in another hour or two.

Jack