how to remove space between browser and the content

[xeon1]

I tried changing margins and looked for solutions all aroun the web but it seems nothing works for me.
my website is this - http://www.scuniverse.org
how can i make it wider? or remove the space between it and the browser?
I'm viewing the website on 1280x1024 resolution and on the more common resolution is seems that the problem is solved and there is no space.
I want it to be optimized to my resolution also.
my aim is to be able to make the CMS page look like the CMS page of vbulletin's official forums(the default style on every vb CMS)
How can I do this?

Thanks!

~Xeon1