FWIW, 192.168.0.* is the reserved class C address range I was always taught to use for non-internet LANs.
Anyway. I assume that all 3 machines have the same subnet mask (255.255.255.0) and the same default gateway.
Have you tried the W2K box in a different port on the switch - in case you've plugged into the uplink by mistake? Have you tried rebooting the switch with all three machines powered up?
Also, just for a laugh - try installing NetBEUI on all three boxes. It is a very trivial-to-setup stack as it only requires each machine has a name and is in the same workgroup, but should prove connectivity between all three boxes...
HOSTS is a text file that is used by TCP/IP if DNS isn't available. It contains the IP address of each machine, along with it's name. For everything to work, though, this file must be on every machine on the network - hence for more than 5 boxes you use DNS.
Let me know how you get on, and I'll keep thinking...