Header.php de body nin altına alttaki kodu ekle .

<div id="sabit"><a href=""><img src="fixed.gif" alt="" border="0" /></a></div>

Css yede alttaki kodu ekle .

#sabit
{
z-index:9999;
position:fixed;
_position:absolute;
bottom:0px;
right:0px;
clip:rect(0 100 85 0);
_top:expression(document.documentElement.scrollTop +document.documentElement.clientHeight-this.clientHeight);
_left:expression(document.documentElement.scrollLe ft + document.documentElement.clientWidth - offsetWidth);
}