Windows.old file issues when trying to install plugins

Ok so what is happening here is I try to install a plugin and get re-directed to use a non existant file to try and launch it. I am unable to select a different installer for the plugins and when I do it resets to this.

I have tried running the file association, deleting all file associations and almost every other common fix to similar issues. I have also tried manually installing plugins but I am unable to change file type for TS3 files either. Help is appreciated, thanks!

Just scroll down in that dialog and click on Choose an app on your PC and then you move to the client path and select the package installer again.