After format/install, ethernet wont work

After formatting and reinstalling Leopard on my Macbook, everything is back in working order, including Airport WiFi, but connecting my ethernet cable does not allow me to use the internet. It says it's connected, but always tells me it has a self-assigned IP. What am I missing/not configuring to get this working again? I should note it worked fine before the reinstall. I've also installed all the system updates.

Thanks

 

yeah, its set to that