Well, it turns out we were having a small display error on our main nav in ie7.
The error turned out to be an instance of the sticky bug and the the drop downs were not clearing on mouseout.
The nav is working now (we added display:inline to the hover sudo class and height: 1%).
IE 7 can be tricky since it does not follow all the established web standards for css.
All are easy to install and can import your existing bookmarks and favorites.