The image shows a 20px white margin around the top, bottom and sides; we haven't got your code to look at, but it's probably the default body margin.
Try a style:-
body { margin: 0; } in you style sheet or in style tags in the head section like:-
<style type="text/css">
body { margin: 0; }
</style>
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.