To do the Activation of Security Retail card just follow the website McAfee activate & then it will ask you to enter the 25 characters long McAfee product key. Once you have entered the correct McAfee code & other details correctly on the activation screen then you can start the download and installation of your Antivirus Security Online. If you have any issue while doing this please give us a call or simple start the free live help chat with one of our online experts. First, you need to make sure that there are no other security programs installed on your operating system then you need to activate your registration number on the website www.mcafee.com/activate. Once you have completed the activation process you can log in to your McAfee Account and go to the subscription section of your account and then you can see the button there like Add device. Now you can start the download and installation of your McAfee product online.