I've already done that, using Tool Hub to do the Quick Fix and to do Program Problems, as I was instructed by the Customer Support person.

We also did a Sample Company, to no avail.

But I've followed your suggestion and had Tool Hub fix both of the files I work with, one on QB 2016 and one on QB 2019.  It found no problems in either.

After rebooting, I still have the problem.

I'm thinking of uninstalling QB on my PC and installing it instead on my wife's PC.  She has the same Office 2010 that I do.  

Any other suggestions?  Thank you!