OK, you might have one of your items with runaround on, if you've asked it Quark to runaround an item then that item stays locked in place and everything else moves round it. Useful tool for print work but a menace for web designs. Switch it off and see what happens. You may have to fiddle your design or split boxes to recreate the original look.
Adding drop shadows and some of the other format tools creates similar problems, so try removing them, start with a plan box and add features and keep testing until you get the best compromise between look and function.
Better to get good code in, so the posts on how to do that would be my preferred option, but if you don't want to do that then you can make Quark work a bit harder for you.
Vickikate