Please Help if good with Port Forwarding

Hello,
first i would like to say sorry for this very long message. I just could use a lot of help...lol Ok first of all i am only 16. I am very savy with computers, built 3 gaming ones myself and building another one shortly. But networking and port forwarding is a entire new subject to learn. So please dont be to technical since i am still learning.

Ok first i will explain my situation. My parents and i all game. We have 3 gaming pc's im my house. My dad's is the one connected to the router and the modem. Mine and the other one in my room are connected to the wireless router wirelessly. Our network works fine except for trying to create a online game (no one can see it or join it) or join some servers on some games. I have done a ton of research online and have done everything from turning off firewalls to downloading hotfixes. Then a few days ago i was reading about ports and how they affect online games. I learned that ports are like highways that let teh information from one computer flow to another. Which would be why no one can join our servers because the ports are blocked.

So then i started trying some of the port stuff. At first i callled linksys since that is the kind of router we have and since their tech support is located in india they didnt really understand me or my problem. Then after googling it it brought me to this website. I tried following the instructions but i think i might have screwed up somewhere. I did the port one for Call of duty world at war and then checked it with that port checker and it still said it was closed. I thought i did the static ip address right because i was able to use the internet.

So if someone could be so kind and try to help me set this up that would be much appreciated. My router model is WRT54GX2 made bye linkys.



So basically i cant host a online server on any game( call of duty united offensive, Modern Warfare, World at War, Company of heroes etc) becuase no body can see it ( i even have called my friends asking them to look for my server but they dont see it, but i see theirs) and a lot of servers on games (especially Company Of Heroes) wont let me join because of NAT negotiation errors. It would be very nice to be able to host a server so we can kick people for swearing or hacking and stuff like that.

So if anyone can help me with this port stuff that would be awesome.

Right now my router is set to manufacturer defaults so i can start from scratch. Also do i need to do this port forwarding to each computer or just the ones i plan on hosting the game?

And when i type in the router ip address in the url and it comes up with teh setup i see 8 forwarding port's. When you use them all up do you just delete what is in their and keep adding more? Or is 8 all i can have?

Sorry for the extremely long message



Please Help Me!!!