Question : Forcing computer to use cable instead of wireless?

I have two PCs connected to a 2wire 2700HG-D DSL modem/router wirelessly.  I also have an ethernet cable running between the two PCs.  The wireless router is set to allow only two DHCP connections, which both PCs have now.  I have set the wired connections outside of the DHCP range and they have no gateway configured.  That should force the PCs to use the cable when talking to each other. For the first couple of days this seemed to work fine.  Traffic between the two PCs always went across the ethernet cable (evidenced by blinking adapter lights).

I have a large backup than runs every night.  I goes from one PC to the other, which should use the cable.  I noticed the backup is still running this morning.  Without looking, I knew it was running across the wireless connection since it is so slow.  After checking the wireless adapter light on the receiving machine, it is constantly blinking while the ethernet card is solid.  I don't know what made it decide to go wireless.

One PC is Windows XP and the other is Vista.  How can I force traffic between the two PCs to always use the ethernet cable?

Thanks,
Brett

Answer : Forcing computer to use cable instead of wireless?

Yes.  I agree.  That's not the mode you need.  I didn't see the mode I was referring to in the manual.