Windows Activation or Windows Product Activation is a licensing mechanism used by Microsoft to prevent and evade piracy.

Windows activation is used in all versions of Windows Operating Systems.

After the successful installation of Microsoft Windows, the user is presented with the screen that would prompt for license key which would be present along with the Certificate of Authority that comes along with the Product CD of windows.

Once the user enters the product key, the installation would verify if the key is genuine or not.

Once that is verified the user has upto 3 days to activate the Windows Operating System. There are three methods of Activation of Windows:

• Through the Internet.

• Through the Telephone.

• Through the phone line via a modem.

The process of activation is basically checking the product key that has been supplied by the user with the central repository of Microsoft Licensing Servers to confirm if the key that has been supplied is valid.