Norton Antivirus doesn’t remove everything,like INVALIDE ENTRIES.

Every thing I try that says free does a scan then goes to a payment page.

I just got new computer and I’m sending my old one to my dad. It doesn’t run terribly, but I know there is a lot on there that is slowing it down.

I’d like to just do system restore and put it back to the way it came, but I can’t find the disk. Any advice would be appreciated!

apparently my "Norton Security Online" has been cancelled by At&t. now i need to find a good security software program with virus protection and advanced firewall.
and if i do find one should i Uninstall the one that is cancelled?