Forum screen sizes

[MobilTuner]

Hello im norwegian, so i'm gonna try to explane as good as i can
and hope you understand my questions..

Peoples have different screen sizes on their computers,
and i would like to know how to auto config the size on my forum..
Im using screen size: 1152x864 pixel.
and the forum is maximum wide, just perfect as i want it!

But when i for example set my screen to a bigger pixel size,
the forum shrink and gets tinner, something i dont like,
concering the other members that use different screen size.

When i make the screen size smaller than my default, i get scroll
bars all over my forum, that i think its realy annoying.

is there any way to make the forum auto size it self?
the forum is also set to 100% on the admin style --> colors.

[MobilTuner]

Any?

[Code]

try to make it 1024*768 px and see what happened

[MobilTuner]

i get the scroll bar, i have to slide to each side so see the whole forum.