Norton Offline Install
You can even download Norton offline installers for Windows without a Norton account. You just need to choose one that works for your computer + product key:
norton.com/latestns (Norton Security)
norton.com/latestnsbu (Norton Security with Backup, aka, Norton Security Premium)
norton.com/latestn360 (the discontinued Norton 360)
norton.com/latestnis (Norton Internet Security)
For instance, you copy norton.com/latestns and paste the above URL in the address bar and, you’ll be good to go. Further, you may consider using IDM.
For related info, you may review this page.
As for the security program you’re using, plz browse this KB (link is external) and uninstall that software completely, FIRST.