Border question

I’m sure this is a simple fix…but I can’t seem to find it. I notice on alot, if not most flash sites, there is no background border showing through. Images and designs go all the way to the edge of the browser window. However, when I preview my movies, there is always a border. How do I fix this?

Also, is there a secret to the publish settings. I have been using the “percent” setting because it seems to match my movie while everything else is tiny and off center.

Any help would be greatly appreciated!