Update:

I spoke with a very nice and knowledgeable woman at QB support who acknowledged that this is a widespread problem that has occurred since a Windows and QB update over the past few days.  

On one of our machines, I was able to update everything, drivers, firmware, BIOS, update the payroll update in QB and reinstall all QB updates to get it to work.  But, these fixes did not work on two other machines.  I had previously changed everything suggested by Microsoft and QB for this error (which included a Windows Registry edit, changing the permissions in Excel, etc, etc), so I don't know if these aided in the one machine working and not the others.  I can't replicate the success on the other machines, even when I duplicate all of the actions I had done to the one successful machine.

At this point, at a loss for how to keep the employee's machines working until either Microsoft or QB issue a patch.