NO INTERNET ON 1 PC in 5 PC network

Had a network consisting of a WOW cable line, lynksis wireless/wired router 2 wired Desktops 1 wiress desktop and 1 wireless desktop.I disconected it for some odd reason. and hooked everything up the way its supposed to go set all the stuff up and all of them ecept one, whitch worked perfectly before, work. I cannot get the internet comfigured on one of the wired desktops. It is running windows XP and the computer recognizeds the Network connecton, just no Internet. also, before this i was always able to plug my cable moden into my Pc directly throuhg cat5 cable and it would work. THis does not work either ANY help. I'm not a moron with pcs i think there is just some stupid thing i forgot to do or something with that any input will help THANKS

Dont forget to swap cables with a working machine, a small damage have happened in the connect disconnect.... its worth a try