Shield up test. some ports open. what does it mean?

OS windows xp pro sp3
zonealarm free firewall
free antivirus program

I ran shields up tests
link https://www.grc.com/x/ne.dll?bh0bkyd2

Tests all said ok.
But runing common ports test, it said that a ftp
and a telnet and a http port was open.
The rest was closed.
Shield up's piece of advice is to close the ports.

Can you in plain english explain what it means, that the ports are open?
And how do you know wheather a port is supposed to be open?

Thanks.

Your computer has virtual ports as well as physical ports. You can have around 65,000+ virtual ports on one computer. What that website is telling you is that all ports are closed except for the ones the most likely cannot be shut off. FTP port is for transferring information like an executable or when you are downloading something off the internet. A telnet port is what your computer will use if you establish a remote connection to another computer, server, router, etc. It will most likely be open, but disabled. As for your HTTP port, thats port 80 and thats what your computer uses to bring up webpages.

These ports are standard, and are needed when your computer operates on the internet. You are completely protected as long as you have anti-virus software and a firewall of some sorts, theres nothing to worry about.