Combobox drops up in IE 8 and it works correctly in IE 6

I have a simple select/combo box with 100 options in the middle of a HTML page. When I open it in IE 6 it appears fine dropping down with a few elements displayed and a vertical scroll bar. In IE 8, it opens upward. Looks like it drops down till it reaches edge of browser screen when it has few options and then opens upward for new options added with a vertical scroll bar. Is there a way the select box can be adjusted to appear in IE 8 similar to IE 6?

Thanks Ravi

This is down to the browser/os that your site is being viewed on - you can't control this, bar writing a custom javascript select box, which I personally don't like. Let the OS control how the form entry fields look and live with it.