Have you tried to swap the NIC's order? (ie: have the one that connects to the Cable modem change to connect to the XP PC, and viseversa) also, check to make sure that your drivers are compatible with Vista (i'm sure you've done this, but it never hurts to try again) You might want to try changing which machine connects to the internet first in the network tree, or (my personal favorite) use a router.. that would definatly solve many issues, that and you won't have to daisy-chain your computers to get a connection on one. Let me know if this helps.