Dell Latitude D631 (Early 2009) - Manual (Page 64)

64 Using Multimedia
Microsoft Windows Vista ® Operating System
1 Click the Windows Vista Start button, , and click Control Panel→ Appearance and
Personalization.
2 Under Personalization, click Adjust Screen Resolution.
3 Under Resolution: click and drag the bar to reduce the resolution setting.
4 In the drop-down menu under Colors, click Medium (16 bit) and click OK.