Thanks SmittyChat.
I've done all . I was somewhat hopeful when I noticed that on this new computer, the NVIDIA audio was updated (although nothing is connected to it).
But no luck.
uninstalled, reinstalled drivers
Ran compatibility mode - but the driver only allowed W8, W7, W XP. When running in either of those, it mentioned that "at a minimum windows Vista must be installed" and stopped.
Ran it as Administrator without compatibility ( I am an admin, but thought, why not)
Went through everything the website mentioned.
I can play the left & front in stereo, but when I switch to 5.1 and test, nothing from the center, rear and woofer.