Top Menu Alignment problems

Hi,

Please see attached screen shot for a problem I am having with the top menu. At times if I navigate away from the page and come back, all menu items now appear under the "Home" option in a vertical list. Moving the mouse around will usually bring the menu options back to their original position. My browser is IE7. I have only briefly tested it with Firefox(3.0.5) but havent yet seen this behaviour. Have you seen this problem before and if so, how do I resolve it?

Thanks.

Can you give us link to your site, so we could inspect the page?