Not sure how common this problem is, i cant view the video screens on youtube with Firefox, but i can with Explorer. Theres the same issue with a 2 other media dumps i visit but most of the time its fine, its just Youtube and a couple of other sites.
I get a message :
Hello, you either have JavaScript turned off or an old version of Adobe's Flash Player. Get the latest Flash player.
Turned on and have the latest version.
Sorry could one please move this to the Tech Support.