Video recorder problem

Hey, I got a screen recording program, which lets u record parts of movies from windows media player, you tube, etc. But, when I try to 'capture' a movie i play from a dvd on my computer, when i play the new .avi movie back, i can ear audio but can’t see anything. BUT, when i record a youtube video, i can see the screen.
What can i do so i can see the video that i record from the computer?