You need to "activate" Windows Vista.
Click on the blue Vista start button, then click on "Help and Support".
In the "Search Help" box type: Activate and press the Enter key on your keyboard.
Next, click on "Activate Windows on this computer" and then click on
"Click to open Windows activation". Once you have activated Vista, please
visit: http://www.microsoft.com/genuine/ and click "Validate Windows".