Problem Setting up W2k

HI.
I got a little problem, here is the scenario.
I have 3 PCs at home with W2k pro. 1 of them has 2 NICs, the Network is configured with the address 192.168.0.x. Th 2 NICs in the "main" Computer have 192.168.0.1 y 192.168.0.3. That PC is capable of accesing the other 2, but they can't access each other.
Every time i try to access 1 of the PCs from any of the others, it asks me for a Login and Passwd.
We had WinXp, and It automatically created a kind of bridge for the 2 NICs, and everything worked just perfect(If I may say so, considering I'm working with Window$), but we had to change for some reasons...
What can I do for the 3 PCs to access each other, and without them having to ask everytime for login and Passwd?
Any suggestions are welcome,
10x.

file and print sharing enabled?
make sure same account name/password are on all pcs.
make each account an administartor
make them all the same workgroup