Reference:
Is Norton enough?
It's an industry standard, but it should be kept up to date. Also Norton is for anti-virus. I don't use it so I don't know if it includes firewall protection as well. Some versions of Windows do include a firewall. The simplest way to check on a Windows pc is to check Security Center from your Control Panel. You should see that both Firewall and Antivirus are on. You can also check there which firewall is in operation and which antivirus s/w is in operation. Note that some routers have firewalls in them - I'm not sure whether these would appear on the Control Panel.If you see that there are two different firewalls in operation, you should decide which one you want on and turn the other off. If you have 2 on at the same time. this can cause conflicts and slow down your computer. There is probably a warning that there are 2 firewalls on and advising you to turn one off. This does not apply to anti-virus s/w as fas as I know though I only have one anti-virus s/w on.