You will see this message if Windows is running in notification mode. To use all features of Windows, select the option on the screen that will best resolve the problem.
Activate Windows online now. If you did not activate Windows within the 30-day activation period, or you typed a valid product key but might have ignored previous activation notifications, select this option to activate Windows on the Internet.
Buy a new product key online now. This option will take you to a webpage where you can buy a Windows product key.
Retype your product key. If you mistyped your product key, or haven’t yet typed a product key, select this option.
Show me other ways to activate. If you did not activate Windows within the 30-day activation period, or you typed a valid product key but might have ignored previous activation notifications, select this option to activate Windows with a modem or by phone.
Also select this option if you made a hardware change that requires activating Windows again and you did not activate Windows within the allotted three-day activation period. Choose to activate by phone.