As of Friday night, all is well. I'd had to complete a few projects and had discovered another issue; namely that anytime I tried to insert a module into the ProChannel, the program crashed. It seemed unrelated, but I started chasing down some other paths that Microsoft offered. The system file checker repaired some things, and couldn't repair a couple other things.
Thankfully I have a son who works as a network geek, and I called him up about the system file checker results. (hate doing that, cause it reminds me of how my mother would call me about computer issues
)
What he had me do was delete EVERY instance of Microsoft Visual C++ Redistributable in my Programs and Features in the Control Panel, deleting the most recent first and working backwards to the oldest. He said the order of deleting this way was important.
I then downloaded and installed Microsoft Visual C++ 2015 Redistributable Update 3. It's a little different that the one in the support link. this is it:
Following that, he had me disable the .NET framework in the Windows Features, reboot, re-enable, reboot again. After which I reinstalled Platinum. This time the installation was error free!
I'm including these steps in case somebody else is dealing with this. Because I had gone to the Support link and had downloaded the Visual C++ updates, clean installs, and everything else multiple times without success. The important thing seemed to be uninstalling all the C++ updates in order of most recent to oldest, then installing Update 3.