I am afraid you fell into the trap of attempting to structure your site with absolute DIV's.
Read this to learn why this won't work
If you wish to dip your toes into the cutting edge of grid and responsive designs, see this:
Hopefully, others will post suggestions for less ambitious designs.
Start over with a pre-built CSS layout that does not rely on positioning (view source to see the code)
Default CSS positioning (none/static) is all you really need for 98% of layouts. Alignment of elements is achieved with CSS margins, padding and floats.
Just so you'll know, resolution has no effect on the rendering of a webpage. A given webpage will look identical on ANY resolution screen, provided you look at it in a browser viewport that has the same width. This suggests (correctly) that the limiting variable is not resolution, but browser viewport width. If you want your page to adapt, then use the browser viewport width to determine how it should adapt, not the resolution. And by the way, I completely agree with Nancy's suggestion and Ken's analysis.