I mean the main navigation part, the Shopping Cart moves under Home.

You can see it by pasting my site

http://www.prommart.com/

in to the online browser view I use and selecting IE 6 & IE7:

http://ipinfo.info/netrenderer/index.php

When I take out one of the navigation cells, it should look okay (although it does show the pink expages nav I'm not using):

http://www.prom-mart.com/