Activating and Validating Windows 7

Windows 7 includes a set of antipiracy and antitampering features that Microsoft refers to collectively as Windows Activation Technologies (in previous Windows versions, these were included under the Windows Genuine Advantage branding). The various checks and challenges in Windows 7 are, in essence, enforcement mechanisms for the Windows 7 license agreement, which is displayed during the process of installing the operating system (you must provide your consent to complete setup). We’re not lawyers, so we won’t attempt to interpret this license agreement. We do recommend that you read the license agreement, which is fairly straightforward and is written clearly enough that even a non-lawyer can understand it. In this section, we explain how the activation and validation mechanisms in Windows 7 affect your use of the operating system.
Entering a Product Key

When you perform a clean installation or upgrade an existing Windows installation using a retail copy of Windows 7, you might be prompted to enter a 25-character alphanumeric product key that uniquely identifies your licensed copy of Windows.

If you choose to install Windows 7 without entering a product key, you might be asked to select the edition you want to install (a file named Ei.cfg, in the Sources folder on the installation disk, can restrict these options to a specific edition; if that file exists, you will not see this list of options). You can then use the installed copy of Windows 7 without restriction for 30 days. Before the end of that 30-day grace period, you must enter a valid product key and activate your copy, as described in the next section. If you fail to complete these steps, Windows displays notifications at startup that urge you to activate your installation; additional reminders appear on the desktop and in the notification area. To make the notifications more visible, Windows replaces your personalized desktop background with a stark black background.