Linksys router

Hello, I have a linksys wirless-g broadband router. It's the wrt54g one. I am using 2 blue ethernet cords to connect from each. The first blue ethernet cord is hooked into my dsl little black and the other end into the first slot of the router ( not the internet slot). The other blue ethernet cord is hooked into the routers internet and into the back of the modem or something on those lines. When I hook it all up to the router and stuff I have wireless internet on my laptop but the desktop computer that it's all hooked up to loses internet. Any idea what I am doing wrong and what I need to do? Thanks.