Ok, I'm back already. I have it working again. Here's what I did.
I deleted the thumbs.db files (don't know if this was needed)
deleted the Caches in C:\Users\UserName\AppData\Local\Microsoft\Windows\Explorer
used information in Thumbnail Cache - Enable or Disable
to make sure that it was set to cache even though i have done nothing to cause it to not be set up. (don't forget to run regedit in administrator mode)
then I Rebooted.
Then fired up Resources Monitor and opened the Library (Music Videos) which has all the directories I am concerned about in it.)
Guess what, I could see the thumbcache_96 and thumbcache_256 being written to constantly as well as the thumbs.db files.
And after all that got done, I reopened the library, and the thumbs all displayed instantaneously.
I am now feeling better.
But there is a bug someplace that causes it to stop working. for me it had to do with restructuring the directories ....