How do i change my screen size to 640x480.my present size is too large now?

right click on any empty space on your desktop.After that go to the settings tab of the window that opens and then adjust the slider under screen resolution and click ok.How do i change my screen size to 640x480.my present size is too large now?
640x480 is the largest you can get. In any case, right click the desktop, choose properties, choose settings and move the slider and try out resolutions until you get one you like.How do i change my screen size to 640x480.my present size is too large now?
IF USING XP....... GO TO START,CONTROL PANEL,APPEARANCE AND THEMES,SCREEN RESOLUTION
right click on your desktop, choose properties and then there is a display tab where you can choose different settings