Bits and pieces of Norton will be dotted all around in your Registry, occasionally popping up and wondering why you are not still using it, and recommending that you download the latest up-dates, etc, etc, etc....constantly...!
As as been mentioned, the only way to completely clear your system of all traces of Norton is to perform a total re-format of the Hard Drive, and therefore deleting the entire Registry.
Then re-install Windows.
Been there, suffered it, done it, sorted!...

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Paul...AVG.... 8-)...!
Norton not only takes over your Computer System...It takes over your whole life!!....

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Win 8.1 64-bit. DX11. Advent Tower. Intel i7-3770 3.9 GHz 8-core. 8 GB System RAM. AMD Radeon HD 7700 1GB RAM. DVD ROM. 2 Terra Byte SATA Hard Drive. Philips 17" LCD Monitor. Saitek Cyborg X Fly-5 Joystick. ...and a Briggs and Stratton Petrol Lawn Mower.