Unable To Set Up The Server And Open Up The Port?

I've been trying to open ports to start a server on some games that I play.I used a guide that shows you how to set up the server and open up the port, but I can't get it to work.I've tried making an exception in my firewall,but that didn't work, so I tried completely disabling my firewalls. Nothing. I've gone into my router settings and opening a port this way: But it still doesn't open it up. This is what I'm using to check it.In fact, NONE of the ports are open it seems? No matter what port I try to type in on the port checker, it always gives me that same error.

-Both?
-Microsoft Windows [Version 6.1.7601]
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C:Usersack>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : FellowShip[code]....

Who is your Internet Service Provider (ISP)?

-Comcast

What type of Broadband connection are you using?

-Cable

What is the exact Make and Model of your Modem, Router or Modem/Router Combo?

-Router is WNR2000v3, Modem is SMCD3GNV (One I'm renting from Comcast)

What is the Name of the Anti-Virus, Security or Firewall Software installed from the problematic computer?

-Avast! Antivirus and Default Windows Firewall