Making a div fit the initial screen

If I understand correctly (there’s some room for confusion here):

http://jsfiddle.net/zRpNp/

#screenFiller {
    position: absolute;
    top: 0; right: 0; bottom: 0; left: 0;
    border: 15px solid orange
}

You might be after the position: fixed version: http://jsfiddle.net/zRpNp/1/