Thank you for all your hard work! I apologise, I literally was just about to post that I was marking this as solved but you beat me to the punch.
Ultimately, we wanted to upgrade the PC in question from Win 7 right to Win 10 but hesitated knowing that WU was causing problems and didn't want to run into issues during the upgrade. That said, just this morning we decided to go for it and let the Win 10 upgrade run...and it ran without any problems. WU (and everything else) seems fine, thanks again for your offer to help.
I'm curious, even though I won't be able to run those diagnostics I wonder if your gut has an idea about what might have been causing the original problem? Thanks!!
