.NET Framework 4.8 Installation did not succeed. Help?

[Simon34545]

I recently downloaded a program and when I open it it says: "This application could not be started. Do you want to view information about this issue?" When I press yes it just closes and opens again and the second time I press yes it closes and nothing happens. So I searched this up and found this:
https://docs.microsoft.com/en-us/dotnet/framework/install/application-not-started
It told me to use the .NET Framework Repair Tool and the first changes didn't work and I was too impatient to wait for it to collect logs so I tried downloading the .NET Framework 4.8 installer file but the installed quits in the middle of it because "The requested operation failed."
Can someone help me?

 

[Simon34545]

i guess no one has answers

 

[Alexander1970]

Hello.
Sorry,not really.
My first Thought was the Repair Tool since I had a similar Issue a long Time ago with Windows 10.You said you have already used it.So,unfortunately I do not have any Idea.
Maybe write down your already installed Ones,uninstall all .NET Framework´s and re-install it from the lowest to the highest Versions again.
Thank you and Good Luck.