Windows colour scheme is a predefined set of colours, brightness, contrast and transparency (in vista). There are many predefined schemes in Windows which might interest you and suit what your taste of eye is. Though there are many schemes which are just a variance in colours and shades but there are some schemes which are meant to be there with a purpose. Imagine of those people who cannot read the contents of the window because its colour is too dull or is blending with the background colour. According to a study reading White on black is easy than reading Black on White for people who have poor eye sight.
There is a full control panel Windows for selecting the best theme and brightness/contrast ratio in Windows Vista but there also is a keyboard combination to invert the colours quickly in case you want to. The key combination is Alt+Shift+PrintScreen. If you are on a laptop then you would also need to press the Fn key making it a four key combination – Alt+Shift+Fn+PrintScreen. Make sure that you press and hold these keys together and not just tap them one after the other. By pressing and holding those down for more than 1 second results in a beep and a small Window titled “High Contrast” appears. This Windows asks you if you wish to change the contrast to High. It doesn’t actually invert the colours but applies a standard high contrast colour scheme on your computer. This makes easier for people with poor eye sight or readability to be able to read the content clearly. In order to get back to the normal colour scheme you again press the same key combination and it will apply your basic scheme back. Please remember that your aero theme will not work in inverted colours mode and some of the windows components might grow in size to fit in the enlarged text in them. This key combination also works in Windows XP so you can give it a try there too.
To change the colour schemes to other predefined sets right click on the desktop and select Personalize in the contest menu. When the personalize window comes up the first option there is Window Colour and Appearance. Click on this option to get to the colour and appearance page. Over here you can select the base colour and its intensity and transparency. You can also set the brightness and contrast of the colour by expanding the Show Colour Mixer option. To select from a wide range of colour schemes you can click on “Open classic appearance properties for more colour options”. This will open the same old XP style Window in which you will find the colour schemes listed. As you browse through the different schemes the windows also shows you the preview of how your scheme will look when applied. You may notice that the schemes names High Contrast looks quite similar to the one which we invoked by pressing the 4 keys mentioned above.