I've recently upgraded to OS X. My browser of choice is Firefox. I've downloaded Flash 11.6.602.167. Firefox shows a plug in for Shockwave Flash 11.6.602.167. Firefox will not play Youtube or Facebook videos. If I right click and 'pop out' the video on YT it will play. I've uninstalled and reinstalled Flash and when using your trouble shooting site, helpx.adobe.com/flash-player.html, nothing is recognized and no error message is displayed. Can you help. Safari is displaying the same symptoms and flickering on certain pages, eg Top Sites page. Chrome will play videos but I understand that Chrome has Flash embedded in the browser.
uninstall flash player: http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-mac-os.html
then manually download and install: http://www.adobe.com/support/flashplayer/downloads.html
Thanks for your reply but unfortunately I still have the problem. I've searched for any extra flash files, uninstalled, manually downloaded and repeated the process many, many times. I've also followed all of the instructions on the troubleshooting page. I guess I'll have to call adobe tomorrow and hopefully they'll be able to help me.
[topic moved to Flash Player forum]