I'm a retard when it comes to Windows, I need to open a .flv (video) but it won't let me. What would I need to do that, or if I can't, how should I download a YouTube video to open on Windows?
VLC will play flv and a quick google search will get you various websites where you can download direct from YouTube, and there are also add-ons for Firefox which do this.
On my Mac RealPlayer grabs any video on any page automatically.