It's time to enter the product key. Look for it on the box that your Windows DVD came in, in an email that shows that you ...

It's time to enter the product key. Look for it on the box that your Windows DVD came in, in an email that shows that you bought Windows, or on the Certificate of Authenticity sticker, which you'll find on your PC, power adapter, or inside the battery compartment of your laptop. (It's okay to remove the battery, so long as your laptop is plugged in.)