router dosent pick up 3rd computer

[boundlessone]

hey ive got a question. for some reason when i use my linksys router (not wireless) to play wolfenstein enemy territory or any other games it wont pick up a third computer hooked up to it. one of my friends can always see me and another friends computer but if we try the other way around we cant see him. and the strange thing is. its worked before. im trying to figure out if i need a new router or what. i am running windows xp so are all the other computers (xp home) all 3200+ processors and 1gig of ram. ive also tried putting the routers ip into my tcp/ip settings to see if it would do anything and it did nothing. i hope this helps in my question.

 

[Nodsu]

Disable all software firewalls. Your router cannot affect the traffic that goes between the local ports (unless one of the ports is dead).