If you dont get the updates then your anti virus is useless and you may aswell not have one at all.

Norton is rubbish anyway, it slows any pc down ALOT, and anyone who knows anything about pc's will tell you the same

What id do is get an anti virus called NOD32, its very very good and easy to use and it doesnt slow your pc down at all which for me is the best thing

Take a look at there website and you will see its not your run of the mill anti virus
http://www.eset.com/