Hello and welcome to Techspot.
Reinstalling NIS shouldn`t be that difficult. Downloading the updates shouldn`t take that long either.
However, there is a better way.
Symantec/Norton crapware is one of, if not the worst security programme out there, as well as being a resource hogger.
The best advice I could give you is to download the free AVG antivirus programme and the free Zonealarm firewall from
HERE and
HERE.
After you have downloaded those, disconnect from the net and completely uninstall Norton from add remove programme in your control panel. You will probably need to do this in several bits.
Once Norton is gone, reboot your computer and install Zonealarm, followed by AVG. Reboot your system and then reconnect to the net. Run the AVG updates and do a complete system scan from safe mode.
Apart from anything else, you will probably see a marked improvement of your system speeds. This is because Norton is a resource hogger.
Then download and run the Ccleaner programme from
HERE.
Finally run a disk defrag.
Regards Howard :wave: :wave: