Upgrade from 2.12 to 4

I have a new Windows 11 PC.  I installed Fences 2.12 on it and registered it under a previous license.  Everything was great until I decided to purchase 4.1.9.2.

I downloaded it and installed it.  I didn't receive any warnings that a previous version was already installed and that I needed to remove it, nor did it say that the previous version would be overwritten.

After installation, the installation program stated that I needed to restart my computer.

THAT is when all 773H broke loose.  

After the reboot, the fences were not as before.  The light gray was now dark gray.  The titles were no longer white but black.  Some of the fence's titles were no longer at the top but at the bottom.  When I clicked on the tab to register the program, I got an error message stating that there was a conflict.  Looks like both versions were still installed; one on top of the other.

At one point after forcing the uninstall, all desktop icons as well as most of the taskbar icons disappeared.

I spent 6 hours trying to uninstall both versions which included restoring from Sunday's backup twice.

What is the proper way to install Fences 4.1.9.2 on a machine that has Fences 2.12 so that 4.1.9.2 is the only version on the PC so that it can be registered?