After successful installation of Norton product, the next and important step is to activate Norton product. Following are the steps to activate Norton Product purchased online:

To open the Norton Product, Double-click on the Norton icon.
place the Norton product key on your registered email address.
Enter the 25 characters alpha-numeric product key code in the box.
Click on the Activate, to activate the product
Follow the instructions appear on the screen to complete the activation process.
The steps to activate Norton Product purchased offline:

Go and click on the activation page on the Norton website.
Enter your 25 characters alpha-numeric product key code.
Click on the Sign in option
The product is successfully activated on your system.
If you are facing any difficulty or found any error, then contact the Norton customer support. The experts and technicians are certified professionals and available 24*7 to assist you. The team of Norton provides you an instant solution. For quick support, dial the toll-free number of Norton customer support or to get instant support visit www.norton.com/setup.