I've just recently installed (and updated) Bitdefender Internet Security 2011 on a Windows 7 HP 64bit PC. When I went to youtube.com, the flash player plugin for Firefox is completely blocked. The container that usually has the Flash Player was just all black, no controls or anything. So after searching around I found some people had resolved the problem by "turning off" Bitdefender, which I take to mean just turning all the switches to off in the preferences, and also disable the BD plugin (anti-phishing) for firefox, then reinstall flash player and turn BD back on. This didn't change anything for me, and Firefox was also in BD's firewall whitelist.
I avoided the problem by switching to Google Chrome, but even before I had installed it I turned off all the items in the preferences window. Youtube and other sites with flash seem to work find in chrome now, even with Bitdefender's preferences all switched back on.
I've seen this problem before, but most other people could solve it by doing the reinstall of flash.
