Actually, I installed Office Pro all at once. But, as I stated earlier, the original HP Windows had Office stuff partially installed, probably for 365.
The problem didn't start happening until I started Access, and since then it's a steady stream of "unauthorized changes blocked" security messages and occasional hangs for Access and Outlook.
This makes me wonder if you have a consistent installation. More precisely, at that moment that you installed Office Pro, was your PRIOR installation properly removed? We have in the past seen "remnant" issues where a prior installation had some leftovers to dodge and trip around. This might sound crazy, but look at KitaYama's suggestion of doing a fresh install or recovery of Windows. In the worst-case scenario, you would need to re-image the Windows on your system, then on that refreshed image that has never seen Office, do a "virgin" installation, being sure to install with uniform "bitness" (32-bit recommended). Replace your data and move forward from there.
Otherwise, the only other way I could see to do this will sound even crazier, but ... remove Office Pro entirely. Install 365 of whatever bitness was installed before. Now REMOVE 365 completely. Finally, reinstall Office Pro of the desired bitness. This is intended to use the deinstallation code to remove any remnants so that you have nothing left over from O365 OR Office Pro. It is that, or re-image Windows, which means backing up all of your data and reinstalling everything ELSE that you had on your system.
While you are at it, verify that when you do the installation, that you do the final installation including Access and Outlook with uniform bitness.
As to what you should have seen in the Tools >> References jaunt, there is a section under the "list" portion of the little pop-up references form that would include messages such as "Missing" or "Broken" for a reference that had become somehow "out of sorts" - and if you found one of those, you would know to uncheck and then separately assert the desired reference... if you could do so. But you said they looked OK so there went that idea.