Windows 7 Display Settings / Configuration
1. Right-click any empty area of your desktop, and then click Screen resolution.
2. Click the Multiple displays drop-down list, and then select Extend these displays, or Duplicate these displays. Note If you cannot see the additional monitor(s) listed, click Detect. If does not work, try restarting your computer and do step 1 to 2 again.
You may also use this screen to arrange your displays to match how they are set up on your desk. Simply click and drag the monitor you wish to move to the proper location.