|Are you saying you have a genuine Norton utility installed and it's generating the message?|
Meanwhile run a few cleaner utilities as you may have acquired a pest (malware etc.).
Run adwcleaner, Junkware Removal Tool, (JRT), malwarebytes (free version). Retain any logs generated as possibly one or two others here may suggest you post them here for further input.
Do not pay anything in response to the message you are getting; nor are any of the above utilities. Those utilities are free, safe to use, regularly suggested here.