in ie7 the entire wrapper does not show up but forces a scrollbar to see the content, while the header does not move. in ie8 there isn’t this problem. is there a way to fix this with overflow:hidden while still displaying the content?
Can you post a url so that we can see the page in question?
Hi Welcome to Sitepoint 
As Phillip said above we will need a link or at least the html and css before we can point you in the right direction this could be a number of issues.