// Window scrolling with fixed position box in IE
window.onscroll = window_onscroll;

function window_onscroll(){
  var el1 = document.getElementById('box3');
  if(typeof(document.media)=='string')
  {// only do this for ie
    var s;
    // scrolling offset calculation via www.quirksmode.org 
    if (self.pageYOffset){s = self.pageYOffset;}
    else if (document.documentElement &&       document.documentElement.scrollTop) {	
        s = document.documentElement.scrollTop; }
    else if (document.body) {	s = document.body.scrollTop; }
    el1.style.top= s+75;
  }
}