ver 1903 build 18362.1016
what crashed was Windows Explorer. Initial failure was that double-clicking on icons did nothing. After 15 seconds, the icon would select, but the shortcut never did execute. Had to reboot to gain normal function.
Decided to reinstall Fences, which did reinstall, and my Fences were intact, but initial issue in this posting, 1x7 Fence that got changed to 2x4, and no way to change it to 1x7, was still present.
Decided then to try the purge, as suggested above.
While executing the purge batch file, the display turned green, with no icons showing, and just sat there.
I was able to use ctrl-alt-delete to access task manager, and log off. When I logged back on, Fences was installed, but all my fences are gone. Icons are still arranged as if Fences was active, even after several reboots. Fences 126.96.36.199 is installed.