: Look for a Certificate of Authenticity (COA) sticker on the bottom of your laptop or inside the battery compartment. This is the most common location for Windows 7 Starter keys.

If you have a valid license but are encountering activation errors, such as error (No product key found), you may need to contact Microsoft support directly. Microsoft Support (USA) : 1-800-MICROSOFT (1-800-642-7676).

Choose and enter your 25-character product key. Support Resources