menu different view with different browser

Here is my site: https://s92328213.onlinehome.us/

I am having issues with this site that doesn’t show the menu correctly between 2 browsers, as you can see below.

FireFox version 10.0 shows the top navigational menus correctly.

Internet Explorer version 7.0 doesn’t show top navigational menus correctly.

Does anyone know what can be causing this issue?

Please help if you can.

Thanks in advance.