Why flv video is not playing in window media player?

Basically, Windows Media Player does not provide a good support to flv format videos. Either you should play them with free basic setup Real Player, or download codecs for flv video. Codecs are files which support the playback of specific video format. They are available for free over the net. You just input 'free codec flv video' as keywords and you will get lots of results to it. Hope this helps.