Thank you for your suggestions. I finally got it working yesterday, but it was a bit of a tussle, so to speak. It started out telling me that the ink cartridges were improperly installed. After numerous reseatings, unplugging the machine for 15 minutes, etc., I finally resolved that (I had previously printed an alignment page adn checked alignment, so I knew the (new) cartridges worked.
On the software side, I had to uninstall what had become two copies of the printer in the printers list and ferret out several other HP printer instances in Device Manager before rebooting the computer and using Windows' driver.
I tired this first with the printer connected directly to the laptop. Once this worked, I tried it with the connection made through a fully powered (AC power) device port, which is needed to run the large double monitors at the work station. Happily, I was able to print the test document again, so all is well.
Oh, I also had to change the port from LPT1 to USB1, per instructions. The USB (3) cable is a two-meter one, also new.