Port 80 Open

[\a:\\\]

On my XP Pro pc, I have both zone alarm and internet connection firewall
running. In addition, my laptop is behind a router (hardware firewall).

Recently I ran an online scan of all my ports. Port 80 showed up as open.
How do I go about closing it and if I do, what functionality would I lose?

Also, I always thought that if I was behind a router, no one would be able
to access my pcs since they are not directly connected to the net, so I
don't understand how this online test could have connected to my pc and
shown port 80 as open.

 

[Kenrick Fu]

Your computer might be connecting to the Internet via a transparent proxy
server via your ISP, as a result the online scan might have only scanned the
transparent proxy server, but not your actual computer.

 

[Alex Nichol]

On my XP Pro pc, I have both zone alarm and internet connection firewall
running. In addition, my laptop is behind a router (hardware firewall).

Recently I ran an online scan of all my ports. Port 80 showed up as open.
How do I go about closing it and if I do, what functionality would I lose?

80 is the port used for the HTTP protocol - IOW almost all Internet
traffic. In Zone Alarm, Programs page look for Internet Explorer (or
any other browser you use) and make sure that while it is allowed access
to the Internet, it is not allowed as a server