Ghostscript in the way of e-mail downloads.

Hello, helpful people!

For more than a year, I've been unable to download PDF's because this 
started coming up on my screen when I tried:

Ghostscript is not found on your system, please download it at 
http://www.ghostscript.com

So I've gone to ghostscript and tried to download Ghostscript 9.15 for 
Windows (64 bit)

After trying to allow the unknown program to make changes to my 
computer, I get:

Installer integrity check has failed. Common causes include incomplete 
download and damaged media. Contact the installer's author to obtain a 
new copy.

Then I notice at the top of the Ghostscript downloads page:

For personal use, use without redistribution, and use with no technical 
support the GNU Affero Public License (AGPL) 
<http://www.gnu.org/licenses/agpl-3.0.html> download is your choice.

There, I see a lot of reading to do, but nowhere to click to download 
anything.

How do I make that Ghostscript message go away, so my computer will 
allow me to read PDF's? For a long time I've been going to my wife's 
login to see it, because I can look at and download PDF's there. But if 
I try to copy the file to a flash drive and put it into my login and 
open it, I can't. Same problem.

Thanks for any help you can give.

Peter