Your System Details List shows multiple Flash plugins. Shockwave Flash 12.0 r0 Shockwave Flash 13.0 r0 Shockwave Flash 15.0 r0 You can find the installation path of all plugins on the <b>about:plugins</b> page. *http://kb.mozillazine.org/Issues_related_to_plugins#Identifying_installed_plugins You can check the Flash player installation folder for multiple Flash player plugins and remove older version(s) of the plugin (NPSWF32) and possibly (re)install the latest Flash player. *(32 bit Windows) C:\Windows\System32\Macromed\Flash\ *(64 bit Windows) C:\Windows\SysWOW64\Macromed\Flash\ You can uninstall the current Flash player version and (re)install the latest Flash version. See this about uninstalling Flash players: *http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html *http://www.adobe.com/special/products/flashplayer/fp_distribution3.html

This seems to be a bit of a copy and paste answer that doesn't answer my question at all.

Looks that it has been removed *http://www.google.com/search?q=cache%3Ahttps%3A%2F%2Faddons.mozilla.org%2Fen-US%2Ffirefox%2Faddon%2Fgpu-accelerated-flash-player%2F *http://webcache.googleusercontent.com/search?q=cache%3Ahttps%3A%2F%2Faddons.mozilla.org%2Fen-US%2Ffirefox%2Faddon%2Fgpu-accelerated-flash-player%2Fversions/