[Frank Encruncher]

All you should have had to do was disable DHCP on the second router and then restart the two computers after the second router.
Your router should assign an I.P. addresses to new devices by itself.

To fix this your going have shutdown the network so everything gets assigned properly

Set the other computers to Obtain IP address automaticially and shut them down

Then set your router back to DHCP(depending on how many setting you play with it maybe easier just to restore to back factory default settings)
Reboot the router
Then restart each computer and run Internet Connection wizard
Each computer should get it's own IP address from the router then.