2 NICs in one box, both won't work at the same time. (Cable company trick to keep people from sharing the connection?)

[Smash144]

Here's the situation. I have two NIC's in my server running windows 2k server. One nic is connected to the cable modem, the other is to another computer via crossover cable. I'm trying to share the internet connection to the second computer through the crossover. If I have my cable nic enabled, the two computers cannot see each other or ping each other. However, if I disable the nic that the cable modem is connected to, the two computers can see just fine. I am sure windows 2k server supports a computer with two NIC's, so I'm guessing my cable company has rigged it so that the cable nic can be the only nic in the computer, in order to keep people from doing what I am trying to do. Does anyone know any way to work around this? The help is *GREATLY* appreciated.

 

[Smash144]

bump:
details of setup:

box 1:
NIC 1 - DHCP - Connected to cable modem
NIC 2 - 192.168.0.1 - DHCP/NAT server

box 2:
NIC 3 - DHCP - Connected to box1/nic 2


NIC 1 always works, box2/1 can only ping/connect to each other if NIC 1 is off.