Why does the appearance (or layout) of my document change when I open it on a different machine?

I created a document on my home computer and formatted it just the way I wanted it. When I took it to work and opened it there, it had completely changed. All the page breaks were in different places and my graphics were out of place. How can I make my document stay the way I want it?

Article contributed by Suzanne S. Barnhill

For an updated version of this article, see http://wordfaqs.ssbarnhill.com/TextReflow.htm.