Actually you could have put all your question threads into this one thread. As mentioned, unfortunately with WMP you may need to obtain xtra codecs to play all the various types of video & audio. Codecs for Windows Media Player for movies can be found at http://nimo.titanesk.com And Windows Media Player 9: k-lite codec pack: http://www.k-litecodecpack.com/ Also GSpot (it's free) will tell you what you need to play a certain file.. just open the file in GSpot and it will tell you. Found at http://www.headbands.com/gspot/
As far as any of the other formats that you might have difficulty with (if WMP & VLC can't play them), AVI Players: http://www.itzalist.com/com/avi-player-download.html Hope this answers all your questions.