Alright, update, and no more posts in a row, I swear!
Tried looking into the copy protection utilities, and decided I am incompetent to deal with that...plus I'm not strongly inclined to work with that kind of thing.
Tried Hyper-V on Win 10. Found out, after weeks of aggravation, that Hyper-V on Win 10 Pro cannot support DirectX, which means it can't support playing RTK. For Hyper-V to offer that support, one needs to have one of the Windows server OS'es. It also might need at least an i7 processor, and possibly needs the Win 8 Enterprise as the VM guest OS. Yeah, none of that's going to happen for me.
My solution: Downloaded and installed VirtualBox. It's free virtualware, supports DirectX if you read the relatively simple documentation to figure out how to do that, and it WORKS! Got a copy of Win 7 working on it, a copy I bought to try working with Hyper-V before I found out it couldn't work out.
VirtualBox will work for any Win OS that can play the PUK. Alternatively, one might get something like the Ubuntu OS for free and set it up on VirtualBox, set up the Wine program on Ubuntu, and play it that way; RTK is supposed to be supported very well in Wine, and I've played the PUK on it before.
Or, you could just set up a dual-boot on your computer, and load up the OS that supports RTK PUK whenever you want to play. But that's kind of a hassle since you won't be able to use Win 10 at all while playing the game. So I suggest going with VirtualBox, it's very easy to work with, and you can still do stuff on Win 10. Then again, I trade save files back and forth over the net with a friend or two to take turns, so I like to be able to do things while it's not my turn. If you don't have such an arrangement, maybe dual-boot would be easier.