I downloaded the newest version of the viewer today and it downloaded an .htm file. I even tried renaming the file to .exe via cmd. How do I install this?

I found the solution, so I'll share it with anybody else who is looking. I was using Opera as my browser, so for some reason it saved as .htm. If you use IE it will download correctly. If you already have the file as an .htm, just change the extension to .msi and it works.