How to Enter Norton product key ?

Visit the URL norton.com/setup, and then go to the norton account.
Sign in if you are an existing user else "Sign up" if you are already a user.
If you are creating an account on norton.com/setup for the first time then complete the verification steps.
Enter the email address and the password of your account, which is registered.
Click "Download your software" from the home page, norton.com/nu16.

Now enter your Norton setup Product key via www.norton.com/setup.
Click submit for further steps
Complete the further process to download Norton setup.
Search for the downloaded file.
Open the downloaded file and perform run norton setup install.
Follow the steps displaying on your computer's screen.
Restart the PC and run a scan task to check whether the Restart the PC and run a scan task to check whether the Norton setup is working properly or not. Make sure to allow the permissions and enable the internet security setting to let Norton setup work properly.

For mcafee support visit : mcafee.com/activate