Screen Of media player

Hi
I'm using Media player on Windows vista, i also have a 22" lcd which is wide
i mean it's Samsung 2232BW,
my problem is that i can not view DVD's and some movies with Media player
exactly!!!
the screen dosen't match and fill all of the sides and it shows the video
square.
i did go to option and devices and tried to change the horizental pixeles
per vertical pixels on disply item.!!!! but it doesn't work and it still
shows like before.
i do not have this problem on the other players such as Power dvd player or
jet audio or............... even WINDOWS media center!!!!
so how should i change this setting and which amount i should set for that
part (horizental pixeles per vertical pixels) as i tried 0.5 0.6 0.07 but
non of them worked out.
thank you