networking with a router fails for one computer

I am currently trying to network a DELL laptop with an old pieced together
system, both are running XP and are connected to a Linksys router. The DELL
connects to the internet without a hitch. However the desktop shows
activity, but it's not receiving any data nor will it access the internet.
Everything is green lighted but nothing wants to go through. I'm also using
fairly new network cards as well, proper drivers installed as well.

Any help or suggestions would be greatly appreciated!

-Dave