Thanks everybody for your kind and fast replies. Just to let you know, i decided to migrate to free software, at least for a while, see how my system takes this and afterwards, decide for Avast or Norton.
So far, i uninstalled Norton 2016 from my system. Windows broke after the installation and i had to restore it. I decided to give a clean Windows 10 re-install and install Avast Free Antivirus + TinyWall Free Firewall, which gives me a very nice and customizable protection layer. Will be probably adding Zemana AntiLogger Free if i feel it necessary. Still have my portable software (antimalware, antispyware, cleaners, and system optimizers).
By now, i noticed a clear system performance increase, less random lags, and even better internet speed.
Will keep you updated on how my system behaves. Thanks again.