Let's see if we can get your laptop connected to the Internet.
First, I have some questions and a few instructions for you.
(01) Is this a new (to you) router?
(02) Do you already have one or more computers connecting successfully to the Internet using this router?
(03) If yes, are any of them connecting wirelessly?
(04) Have you recently (at another location for example) successfully connected this laptop to the Internet? If so, did you connect it "wired" or "wirelessly".
(05) Are you trying to connect your laptop to your router "wirelessly" or "wired"?
(06) If you are trying to connect the laptop wirelessly, turn off your laptop's wireless radio and connect the laptop to the router "wired" instead (using an "Ethernet Patch Cable"). Once we've established that the laptop is capable of connecting to the Internet via the simpler "wired" connection, then we'll move on to the more complex wireless connection.
(07) Please, go HERE
to download the manual for your particular router. You will need to determine the version number of the WRT54G model 1st. There are instructions there that will guide you through this.