Why does the screen icons or fonts become jagged when I change the screen resolution ?

Why does the screen icons or fonts become jagged when I change the screen resolution to 800x600 or 640x480 ?
or
How do I disable the internal LCD expanded mode ?

Many LCD screens are hard wired to a specific resolution and must be run at that resolution for optimal visual quality. The internal LCD display's screen area for the VAIO notebook is set to the 1024x768 by default. If the screen resolution is reduced to 800x600 or 640x480, the fonts and icons will look jagged. This is normal since the internal LCD was set to expanded mode by default, the display will try to expand itself to fit into full screen mode. Hence the icons or fonts will look jagged.

To disable the expanded mode of the internal LCD, follow the steps below:

1) Minimise all the opened windows and right-click at the desktop area.
2) At the display properties, select [Settings] and click at the [Advanced] button.
3) At the [NeoMagic MagicMedia256AV Properties], select the [NeoMagic] tab.
4) At the [Internal Display] field, uncheck the box for [Expansion] and click on [Apply], then [OK]

The screen area would be reduced to a smaller size and the icons and fonts would appear normal now.