Hi,
I gave up on Norton as I updated my yearly subscription and then a few months later I was informed that updates are no longer available for my version. What a rip off.
Either your version of Norton has a corrupted file (hence not remembering the updates) or they are being blocked by a firewall. Try disabling the firewall, then manually get the updates from Norton and then re-enable your firewall.
Most of the anti-virus programs out there that claim to scan your computer for free, tell you false infections to scare you into buying their product that will remove them. Some of them are viruses, so when you pay to have these false infections removed, they actually install a virus!
I use AVG anti virus, it is free and so far it has not let me down. Others you could try are;
Avast home edition.
Avira Antivir personal edition.
Bitdefender 10.
Hope this helps.