Other threads don't help me because I don't have RealPlayer installed. This is a fresh install of Windows 7 with a fresh install of Firefox and a fresh install of Flash Player. The Shockwave Flash plugin is present in my addons, so I know the install finished. Firefox and the system even have both been restarted. The only other software I've installed so far is Avast, and I don't see any information anywhere that it interferes with Flash on Youtube. That being said, I tried disabling its extensions in Firefox and it makes no difference. All the controls for videos load, but the video itself doesn't. Firefox 14.0.1 Shockwave Flash 11.3.300.271