Replying to Anyone with a Linksys router, please read....

i have a Linksys wireless-g notebook adapter WPC54G and need to configure it....i've been to a few portforwarding sites and they tell me to paste the ip adress in the adress bar. when i do that a username and password thing comes up and i'm suppose to have an account. just i never set one up and i tried reinstalling the software but there's never a time where i get the option to set one up...so if anyone could help me out, that wuld be great...my aim is FreeWilley81