The best and the easiest way to fix the particular error is to exit from all the running applications in the system and then restart it. After that try opening the Norton anti-virus software and if the problem still persists, then execute the steps accordingly. For that, you will be required to first uninstall the software and then proceed further

• Open the Norton main page and sign in by entering your login credentials.
• Now move to the Get Started Window and click on ‘Download Norton’.
• Agree to the terms and conditions and download the software.
• Open the Setup.zip file and double click on the Norton product installer.
• Install the application and when a prompt appears to enter your admin password and now click to Install Helper.
• Now complete the process as per the on screen instructions.
• Now restart the system and see whether the issue has been resolved or not.

If the problem occurs persistently after applying the method, then make sure to talk to the Norton tech support number to fix the issue on a permanent basis.