hummm. Ok, other thing that comes to mind is are you connected from pc to router with maybe a crossover cable instead of a straight cable. Most often, the cable from modem to pc was a crossover style.
A straight cable from pc to router, note that your not in the uplink/internet port and in a normal wired port, and sending your browser to the right address [url]
http://192.168.2.1[/url] should get you to a login screen. If that doesnt, some where on the router should be a reset button. Id reset it to make sure everything is at default so you know you have the right ip address.
With everything connected, pc to router, router to internet, can the pc see the internet?
if so we can do a trace route command and find the routers ip that way.
assuming this is xp you would so start>run>type in cmd> enter
at the prompt type tracert
http://www.google.com (or any site u prefer)
hit enter and it should look similar to this

- trace.jpg (81.82 KiB) Viewed 4735 times
note the first hop with the 1ms ping
the first one should be your routers ip