The height of, at least, the Support menu is too large for my (1024x768) laptop (let alone my netbook, which has 1024x600 or so).
When I run Firefox in normal mode, the cutoff point (last item I see) is “Top country finders” (on theright); when I use F11 to make it full-screen and hide the start menu bar, the last item is “Top Karma” (on the left). Scrolling down is impossible as the menu sticks when the site is scrolled.
Maybe a “styled” menu like the one you’re currently using has reached its limit, and a different form of presentation may help? This is not the first time limited display real estate (especially on laptops) has caused problems… the different form need not replace the current one (it could be choosable, and even not the default).
At the very least, a ▼ button that manually scrolls those menus could help… or, trivially, make the surrounding div into max-height:100% and overflow:scroll (except max-height is not accepted by all browsers, unfortunately… I really hate CSS, and I have to deal with it at the orkplace way too often…).