I am operating windows 32 bit with Internet explorer and had with no problems until I installed Firefox. While using firefox, it didn't recognize my flash player and said I needed to install the latest version (126.96.36.199). during the installation, it said "Olny a single instance of this application can run". I tried several times with the same results. I've searched the adobe forums and tried several of the possible fixes but nothing is working. I tried to uninstall the flash player and reinstall, but that didn't work either. At that point, flash player didn't work in Internet explorer or firefox. I then uninstalled firefox in hopes to just get back to being able to work in Internet explorer. At this point it is still not working. Please help.
Restart Windows, then download the executable installers from http://helpx.adobe.com/flash-player/kb/installation-problems-flash-player-windows.html#Ins tall_in_a_firewall_proxy_server_environment and save them to disk. Close all browser windows and run the downloaded installers.