liTtle_3 :
I have opened the firewall on the computer and port 80 is forwarded to a different computer.
There is a high probability that the PC is not allowing those ports through. You might consider temporarily disabling the firewall altogether and testing your server.
Since you can successfully forward port 80, it's not likely a problem with your router.
ISPs are more prone to blocking a web server port (i.e. 80) than a game server port, but you may want to check with your ISP to find if somehow those ports are being blocked.
Not sure what else to recommend, other than trying to use the server on a different PC.
edit for clarity