I "fixed" the vertical issue, by using the custom css, thanks. I think the page looks better with the three related products laid out horizontally rather than vertically because they can all fit on one horizontal row and not take up so much white-space.
I haven't been able to fix the navigation on the Shop page though. I have the plugin WP-PageNavi as well as WooCommerce 2.0.4 and Wootqiue 5.5.5, could WP-PageNavi be causing the problem?
I tried disabling WP-PageNavi and clearing my cache and everything but that doesn't seem to get rid of the two navigation bars at the bottom of the page.
If you scroll to the bottom of this page you will see what I'm talking about: http://www.laptopdealscentral.com/shop/