YoutubeX help?

i can download videos from YoutubeX but i cant play them because I dont have the proper player





I have Windows Media Player but that wont work.





What is the most used extension for these videos ?





Thanks
YoutubeX help?
try to run using flvplayer,


http://www.download.com/FLV-Player/3000-...





or install k-lite codec pack for your window media player to run flv videos