I recommend ACe Mega Codecs Pro
http://www.softpedia.com/public/cat/...1-2-7-10.shtml
It comes with BSPlayer and Media PLayer Classic(Not made by microsoft, just looks like media player, and it can play any video files, even real media)
BSPlayer is the most stable video player I have ever used. Some video files I play with other players that would crash int he middle, play just fine with BSPlayer.