Divx/DVD Rip doesnt go full screen

[blicious]

I'm totally a beginner with downloading and playing divx, but I've just downloaded a movie from Kazaa Lite that is a divx/dvd rip...it looks sweet but whenever I play it in Power DVD or media player I cant get it to go full screen or at least expand to normal widescreen, right now it just plays in a box shape....I wanna get rid of the the right and left black portions...like a normal widescreen...