Hello,
The way this usually happens is when the width of the webpage is larger than the width of the viewer's browser. For example my sister likes to keep her browser window at a very small width and is always complaining that she has to scroll horizontally to see the whole page. Of course she is the only person that I know that keeps her browser window that small.
One way that your webpage can be larger then the normal viewer's browser window is if you have something like a large graphic. Say you have a picture on your webpage that is 1000 pixels wide and the viewer's browser window is only 800 pixels wide. Then the viewer is forced to use the horizontal scrollbar to view the entire picture.
Another way to force your webpage to be wider is to use a <table> width that is very large. Then if the viewer's browser is not that large, he will have to scroll.
The way to prevent this (besides not using extremely wide pictures) is to use percentages for the width of the <table>. Instead of width=1000, use width=100%. In this way the width of your webpage will collapse as needed and there will be no scrollbars.
Hope this helps.
