Windows downgrade to 2.2.9 failure to start

[Jason Dunham]

I have used Gnucash 2.2.9 for about 18 months, running on Windows 7 since
July.  Recently  I tested 2.3.8, installed to a different Program Files
folder, and loaded my file and it showed the splash screen and progress, and
then quit silently at or near the end of loading.

I then uninstalled 2.3.8, and 2.2.9 failed the same way.  I reinstalled
2.2.9 and it still won't load.  What should I try next?