Horizon wont open

I’ve seen and read a few of these topics now, but I have done all they have suggested.
I have installed Net Framework 4.5
I have turned my Anti-Virus off
I have allowed Horizon through my Firewalls, and I have turned my Firewalls off.
I have turned my internet connection off.
And I have tried to run as Admin on all of these steps.
I have also tried to uninstal and reinstall, and reset my computer.

What I get, is much like everyone else it seems. I get the Horizon logo appear on screen and then a pop up saying that Horizon has stopped working. When the internet is turned off, I get a pop up saying Failed to connect to Server, and then the window that Horizon has stopped working.
Basically, I have done EVERYTHING suggested, and still can not open the program. Any help will be appreciated.

You need to make sure you have .net framework 3.5 not 4.5. 4 and 4.5 do not include 3.5 which Horizon is built on.

Done that, and still wont work.

I only have Net Framework 4 and 4.6 and it’s working fine for me.

Windows 10 has it built in and I believe 8 does also.