Well, Microsoft Tech Support bailed me out...bet that doesn't get said often...
I called them with the issues listed above (Office 2010 and HP Printer software not installing). I spent at least 7 hours on the phone with them the last two days. Today they tried several things including removing and reinstalling the .net framework and editing the registrys with no success. He then tried a reinstall over the top of the current W8.1PMC, same errors as before. Tried another "clean" reinstall with no files from the old software, again, same errors. In the end with the "clean" install not working, I agreed to downgrade to W7U and he provided my with an ISO and a Key, but he was at the end of his shift and left me to make a bootable thumbdrive and install W7U.
I tried to install W7U, but ran into issues with the thumbdrive and an error saying that the drivers were missing (I think that was a USB 3.0 VS 2.0 thing). Anyway, I was glad I ran into the problem because in the mean time I downloaded a W8.1P ISO from the internet and decided to give it a try with the Key that the Tech Support guy used for the earlier installs. This time I formatted the HDD (SSD) before continuing on to install a true clean copy of W8.1P. SUCCESS... I am able to install all the software that was giving me problems before and other things that I didn't realize were issues are gone too.
My only issue that I can see now is that the recovery partition that the Tech set up before one of the reinstalls, is now not showing up in Windows Explorer. I can only see my C:\ drive, the D:\ is not present, but from where I started, that is not a big problem.
Anyway, just thought I would update you all.
One other thing...is MC worth getting? I/we don't watch tv or movies on our laptops, so I am thinking it is a bit of a waste to install it. Opinions?