what program are you using to manage wireless connection?
What is your Understanding(Tech Level if you will) for wireless connections? so i know if i can skip over basics.
you may need to change the security setup on the wireless router if its WEP2 your computer might not have a capable card as it was not prevalent in 2004.
Other useful information:
-Does router work for other computers?
-what kind of modem do you have?
-Router security setup(WEP,WEP2,open,etc)
-when you plug the cable connected from your modem to your router into your computer do you have internet?