"Only a single instance of this application can run" error when installing Flash

[TheMonkeyGamer]

I deleted Flash Player when trying to solve a Shockwave Flash Google Chrome issue, and after being unable to solve it I switched to Firefox. I now can't get the installer to open. I double-click on it, it asks me if I want to run it. I click Yes, then the window closes and the installer doesn't open. When I try running the installer again, I get the error message "Only a single instance of this application can run". I have tried everything. I closed Firefox, restarted my computer, and ran the Flash Player uninstaller. I am running Windows 8.1 64-bit with Mozilla Firefox and I am trying to run the latest version of Flash Players as of October 26 2014. Please help!

[pwillener]

Use the offline installer http://download.macromedia.com/pub/flashplayer/current/support/install_flash_player.exe

[jachyra]

I'm having the same problem, also on Windows 8 with Firefox, but when I clicked on the link the page wasn't found. Is there a new address?

[pwillener]

The download link has moved since then: http://fpdownload.macromedia.com/pub/flashplayer/latest/help/install_flash_player.exe