no dont use windows media player classic, Thats only better when playing DVD's
What you need is the xvid codec,
http://www.xvid.org/
xvid also decodes divx formats, I can'nt belive people dont have the xvid codec installed, Its kicks the ass out of divx format plus it also plays divx movies
Ohhh and its free and pretty much all movies downloaded from the internet uses xvid instead of divx these days