Found the problem

I was correct to suspect a Windows update was the source of my font issues.  A little googling led me to this thread and helped me pinpoint the culprit:

I uninstalled "Security Update for Windows Vista (KB3013455)" which impacted TrueType fonts (MS15-010) and my issue is resolved.
Fonts are readable, once again.

I did as the folks in that thread did and uninstalled that particular security update.  My fonts are back to normal now.

Good thing, too.  It wasn't just Times New Roman in OpenOffice that was messed up.  Other fonts suffered, too, including the text in one of my computer games.  And that's just intolerable.  You can't mess with a man's games.

Anyway, all's well that ends status quo ante.  Back to writin'...