When you boot up a new computer for the first time, you get a prompt asking to register the preinstalled McAfee LiveSafe software. In the course of registration, you need to agree on sharing information. In case you agree, then McAfee LiveSafe will get automatically set up during the regular setup process of the system. In case you opt not to choose the Agree option, then also you can activate the LiveSafe software at some other time by going to mcafee.com/activate and signing up.
Please read the originial post here: http://mcafee-activate.mozello.com