I had to reinstall the program from the "renewal" installation link HOSENOSE sent me and it is working now. I had renewed my subscription in late March and I had reinstalled it on my other computers, but not this one. This one is at one of my remote locations.
I'm guessing it may have had something to do with the expiration.
Or something may have happened with the last Windows 10 update on this machine which happened on the same day I noticed the program malfunction ... when I clicked on LOGBOOK under the FILE menu (or F11), nothing at all happened ... no new logbook window, blank, old, or otherwise ... nothing. As if I had never pressed the menu item.
In any event, everything is back to normal and working after the renewal installation was completed ... including access to my current log files.
Thanks again and 73,
Fred
K9SO