I strongly suggest to download and use Miro. It's a free and open source video player that promotes downloading and saving all the videos that sites like YouTube can delete and prevent the public from having access to. You can also create your own channel by using RSS feeds. (I made a couple music video based off of my playlists on YouTube so I could watch them without having to deal with the load times of that site.) I have a mac and it works awesome-sauce-ly on it. They support all OSs.
http://www.getmiro.com/