error d/ling codec (windows media player)

[SHk012]

Hi everyone, i've downloaded a bunch of divx files.. or dvd ripped movie files and i have the main divx codec installed.

Problem is.. some of the movies i've recently downloaded have been giving me msg that say "error downloading codec"
Some.. i dont get sound, but picture. some.. vice versa.
so i was wondering if anyone know how i can fix it by downloading codecs somewhere??

thanks