Online port checker sites saying ports aren't open

[TheMentos]

I googled how to open ports and it told me go in to windows firewall>advanced setting>new rule etc. I want to install a game so I need certain ports to be open and unrestricted. When I used online port checker sites they all say the required ports aren't open. What's the deal here?

 

[napnap]

Hi how are you connected to the internet, is it directly or do you have a router?
If you have a router you will have to do a port forwarding on it, to your ip address.
If you are connected directly you will have to call your ISP, and have them open the ports.

 

[TheMentos]

I'm connected wirelessly to a bell modem. I tried to install the game on a different computer hooked up wirelessly to the same modem and it worked, would that mean the ports are not an issue?