Port forwarding on Thomson TG585v7?

I want to open port 25565 so that I can host servers on Minecraft. I have used the router configuration web page to forward the port to my PC but Port Checker says that it is still closed. From a little bit of research I have gathered that the TG585 is a bad router for NAT and ports and suchlike, but before this ports were easy to open, as I easily forwarded them to my Xbox for Xbox LIVE, but no matter what I try this one will not work. Can anyone help?