Multiple monitors can be a great way to expand the available viewing area for a user's desktop, but not everyone prefers the added space to view programs. If you prefer to display the desktop on only one monitor, you will need to reconfigure the display settings in the operating system.
Click the "Start" button and click on the "Control Panel" shortcut.
Click "Appearance and Themes" and the "Display" icon.
Select the monitor you wish to remove from the multiple display as shown in the "Display Properties" window.
Uncheck the "Extend my Windows desktop onto this monitor" box and close the "Display Properties" window.
Windows Vista or Windows 7
Click the "Start" icon and enter "Display" (without quotes) in the "Search" text field.
Select "Change Display Settings" from the list of available shortcuts.
Select "Show Desktop only on
For Windows Vista, Windows 7 or Mac OS X, the easiest way to move the desktop from multiple monitors to only one monitor is to unplug the monitors you don’t want to use. The desktop will automatically rearrange itself to the functioning monitor.