To adjust your monitor screen size
1 Click here to view Display Properties at the Settings tab.
If you have more than one video adapter and are running an extended desktop, you must first select the video adapter whose display properties you want to change, by clicking on the associated display icon on this Properties page.
2 Click the Advanced button.
3 Click the Displays tab.
4 Click the Monitor button.
Your monitor must be enabled before you can change its display properties. Click here for more information.
5 Click the Adjustments tab.
6 Click the (+) and (-) buttons in the Vertical/Horizontal Screen area to change your screen size.
The (+) and (-) buttons under Vertical Screen increase/decrease the vertical size of your monitor display.
The (+) and (-) buttons under Horizontal Screen increase/decrease the horizontal size of your monitor display.
7 Click OK or Apply to save the changes you have made.
Size controls are not available if both a monitor and TV are set to the same display mode. Click here for information on how to change display modes.
Desktop Help for Windows XP, © ATI Technologies Inc., Version H6.01
the info above is for my radeon 9000 pro could be you need to select correct monitor