Seriously dude, will you please stop resurrecting old threads.
This one is 16 years old !
BTW. Comcast do not make Norton.
Symantec make Norton. Comcast is your internet provider.
Symantec pay ISPs to shove free Norton trials at people (it does not stay free).
If people search first they will find that the quality of Norton is so random over the months, that you cannot trust it.
ISPs could give really free, high quality antivurus, but nobody will pay them to do that.
The final word on choosing your antivirus is;
Look at the comparison sites, and never trust the opinion of a user with no comparison to something else.
Over the past year (2015) Avira has been voted the best by the independent AV test sites, for the most months.
Avira and Bitdefender have been the best free AV over the past year, and currently still are.
If you read this post in years to come, just use the links below and ignore everything in the tread above this line.
Half yearly averages
https://www.virusbtn.com/vb100/latest_comparative/index
Monthly tests
http://www.av-comparatives.org/dynamic-tests/
https://www.av-test.org/en/antivirus/home-windows/
https://www.av-test.org/en/compare-manufacturer-results/