I recently have gotten high speed comcast internet in my home and it works great on my home computer, but when I try to hook it up (by taking the ethernet cord out of my comp and plugging it into my laptop) to my laptop (Dell latitude d600), an error message pops up saying that there is limited or no connectivity. When I try to repair it by pressing the repair button on the pop up, it fails because it cannot renew the IP address (?)

I used to do this all the time with my old internet provider (at&t dsl) but now its not working. PLEASE HELP ME!

Do you have a router or are you going straight to the modem the gave you