1600?! Wow, you must have good eyes. I need a magnifying glass to read anything on my screen at that rez.
First things first. If you aren't going to do a fluid, scalable design, you might want to design for 1024. There are still some folks using lower rez and some sharp-eyed folks using higher, but that appears to be the sweet spot right now.
As for Frontpage, it will do exactly what you tell it to, no more, no less. The first thing you have to do is tell it what you want.
Go into Tools > Page Options and choose what settings you want for your site. Pay particular attention to the Authoring tab and set what technologies and which versions of CSS, if any, you want it to support. Roam around the other tabs and try to figure out what they do, play around with them, and set them as you think you should.
Backing up a bit, before telling Frontpage what you want it to do, you have to decide what you want. First determine a Doctype [w3.org] and make you Page Options settings in FP based on that.
Now that you've got it all set up, keep in mind that, aside from its site management features, Frontpage is basically just a nifty code editor at heart, it really doesn't do anything. So it sounds like you're making some fundamental errors either in your html or css declarations. The best places for help on this are WebmasterWorld's CSS [webmasterworld.com] and this HTML and Browsers [webmasterworld.com] forums. Try to keep your questions concise and, if you post code examples, first try to boil them down to the exact parts that are causing the problems.