Not sure how much more I can offer in the way of help, but.....
First of all, that would appear to be a very old version of the program and may cause you some issues if and when you manage to get it installed and running.
My wife still stares daggers at me because her old Scrabble Complete will not run more than about 10 minutes before crashing on Windows 10.
I notice that they have what they are calling a half price sale on the Full 2018 version of the product for $39.99
Personally, I would uncheck and forego the 2 year download insurance if you decide to purchase.
You can just save the download on your computer or on some external drive if you would need to install again later.
Make sure you also save / print any email or other communication which contains a product key associated with the product.
https://www.paintshoppro.com/en/pro...term=paintshop pro&utm_content=PSP|PT|Main|0^
I have no personal experience with the 4.12 version of the product and do not know how you are trying to install it or what resource you are using to install it from (CD, DVD, ISO, Floppies, etc.).
I do know that it will likely need to be completely installed and registered with the windows registry inorder for it to run properly even in comaptibility mode.
So far, from what I can tell, you are having trouble installing the program.
So that is the first hill you will have to climb.
What media are you using as install resource and if you browse that media do you see something like a "Setup.exe" file?