first of all, how the fuck is that even working?.. all you said is that you have 3 ip addresses for 3 computers.....you know you do have 6 nic's right?...you really need to set up your ips correctly.
eviltechie: yeah you're right proxy is a pain in the butt, and yes thats what this is.
the easiest way to do it would be:
1. enable ICS [internet connection sharing] on the 2k machine [on the internal NIC] >>#2 on my crappy diagram
2. set your SDSL modem to give out one ip address to your 2k machine
3. set every single nic on your network to DHCP [automatically assign] >> #1-5
( well i personally would go static but i'm not sure i want to spend the time to explain all that )
4. set your default gateways to the nic that has ICS enabled on it.
5. get rid of nic #6 disable it or something.. its not in use is it? its not on the diagram purposely..but its the unused nic on the xp machine.
the x's are crossover cables
if you still have problems get some information that will actually help us help you:
on each machine get the output of:
and paste it here.
hope that helps..i got tons of other suggestions but i'm having trouble figuring out what the hell all you wrote. its like a constant run-on sentence.