I generally see this problem on my networks when using an older card that has the IRQ either jumpered or set by DOS driver software, and Windows is trying to assign a different IRQ or memory address to the NIC. Thus Windows knows it has a NIC, and will allow the computer to 'see' itself on the network, but is not actually using the NIC so the computer can't communicate with the rest of the network. If you happen to be using NICs that fit the description I gave, you may want to see what their 'hardware' settings are, and force Windows to use those settings...