What is activation?
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.
The information collected during activation will not be used to contact you.
You have 30 days after installing Windows to activate it online or by telephone. You need to activate Windows before this 30-day period expires. For more information about activation, see Activating Windows 7: frequently asked questions.
If you chose to automatically activate Windows online when you set up your computer, automatic activation begins trying to activate your copy of Windows three days after you turn on your computer for the first time.
You can find your product key on the computer or inside the Windows package—or in a confirmation e‑mail if you purchased and downloaded Windows 7 online.