One other thing I forgot to mention -- I had an HP OfficeJet all-in-one, which included a scanner, connected to my computer wirelessly. I had to remove that to get my Epson Scan to work. Now that it's working, I will reconnect the HP and see if that makes it stop working.
Presently scanning some 4x5 transparencies of architectural work from my pre-digital days that I want to include in a new portfolio of large (12x18) prints.