You must activate Windows within 30 days after installation.
Activation helps verify that your copy of Windows is genuine and that it has not been used on more computers than the Microsoft Software License Terms allow. In this way, activation helps prevent software counterfeiting. With an activated copy of Windows, you’ll be able to use every feature of Windows.
Open Windows Activation by clicking the Start button , right-clicking Computer, clicking Properties, and then clicking Activate Windows now.
If you are prompted for an administrator password or confirmation, type the password or provide confirmation.