Help! Can't open port!

Hi guys, I've been trying to start up a server and play with the idea before buying the space with a host. I've done everything the tutorials say but I JUST CAN'T GET THE PORT TO BE OPEN!!!! I've made it allowed on firewalls, done port forwarding, checked with my isp, and it just doesn't work! I'm running on Win 7 and using a LinkSys WRT54G. I just don't know what to do and could use a experienced ServerCrafter to help me out!

Also, please don't reply with "Just buy one" or "Don't bother". I would like help not hindrances.