Hello Bob David,
I see what you’re doing now. It seems that you don’t have AxCrypt installed on your upgraded computer but that’s very easy to solve.
As you’re on a fairly old operating system/computer, I’d recommend you download the same version of AxCrypt as you had before.
Scroll down the page until you see “AxCrypt Outdated Downloads” and then download:
As soon as you’ve downloaded AxCrypt-1.7.3180.0-Setup.exe you need to install ist. Once you’ve done this you’ll be able to open your encrypted .AXX files just like you did before.