Assuming this is a brand new product to you, and you have the webcam and installation CD?
Read the instruction manual, for installation, when to connect the webcam to your computer, and configuration settings.
Registration comes up automatically after it is installed, or you can click on the webCam in Start / All Programs / Microsoft LifeCam.
Or MS will help you on the phone with installation. 1-800-Microsoft (642-7676)