I had the same problem about a week ago, at least that's when I noticed it. My site look great on Firefox. But when I went into Internet Explorer my text was all the way left and my navigation buttons were on top of my text and picture.
what I found out was we had changed our logo on the top of the page and enter the picture in the center of the page.
in doing so we changed our pixels from 725 pixels with to 875 pixels with. By doing this with the logo and the picture it distorted the page. So it showed up different on different monitors. As soon as we brought the logo and the picture back to 725. Everything fell back in line and we haven't had anymore problems.
DON
San Francisco, the city made for discovering, over & over again!