I cannot get adobe to download most recent flash or reader for Firefox nor can I find a plug-in for either

Question

After my laptop crashed the second day of class, I had to send it away for repair for 8-12 weeks. I have had to reset it up from scratch and have set-up Firefox. There is a online college math program that they recommend using Firefox with. In the past I have never had a problem with Adobe anything. The program also requires the newest Adobe Flash Player and Reader. I have repeatedly tried downloading, rebooting and restarting the the downloaded .exe files for both (making sure there is only one version running at a time in the file folder and in task manager background). I have used all possible settings for adobe products permissions to work across all firewall, antivirus, web protection, Mozilla and my computer systemin general, even Internet Explorer (Hate it).
The files download to my downloads file folder through Firefox, however, when I double-click to install them I get the "Do you want to run", "yes", then "Windows smartscreen is unavailable do you want to run anyway, "Yes", then absolutely nothing happens. No wizards, no installing, nothing or I get a "Only one single instance of this file must run." and again nothing. Tried it with nothing open, but the "install" and with the browser open. Neither works. It's usually listed in |Task Manager Background apps, but uses no memory, no CPU, nothing.
I've also tried contacting the school program's IT division (3 hours) nothing, the program itself's IT department (2 hours and they disconnected me) or the best anyone could offer was use another browser. Can't get the only other option, Chrome, to work on my computer at all! I've tried all Mozilla and Adobe support/knowledge bases/zines, etc... I'm just a Joe schmo not a developer or IT person and a 4 finger typist at best. What I am is 2 weeks behind in my online class and ready to pitch the f#$***g thing across the room. I was able to borrow a laptop from a friend until I got mine back, but that isn't an option anymore.
Also tried finding an older version - no luck, All support sites keep telling me to find the Firefox "Adobe Plug-in" and just update from there. I have searched all Mozilla Plug-ins, add-ons, etc... but nothing, just download(s) for non-adobe flash players that the math program won't use. No matter How much I try to get it to.
AUUUUUUUUUUUUUGGGGGGGGGGGGGGGGGHHHHHHHHHHHHH!!! Help.

Answer 1

For Flash, could you try downloading the "full" installers from this page:
https://www.adobe.com/products/flashplayer/distribution3.html
In the first table, there are two rows for Windows: one for the ActiveX control for IE, and one for the plugin for Firefox. You might want to grab both. And try the .msi files instead of the .exe files to see whether those work better.
Will either of those install?
It's odd that on a newly rebuilt system your More System Details shows that you have a user.js file, which is an optional settings files used to override your previous session settings. This is not part of the standard Firefox installation, so if you did not create that file yourself, you may want to investigate or delete it. This article has more information on that: [[How to fix preferences that won't save]].