how can I play these movies?

[Angrist]

I've downloaded some movies for when we're on vacation (taking our laptop with us), but I can't play some of them.

Like an X-Men DVD-rip. The filename ends on .avi , but I only hear the sound, I don't see the movie.

I probably need DivX or something, but could you tell me if that's it and where I can get it?

Thanks!