I started (after connecting) running Network setup wizard on Comp 4.
Network and Internet connections
Set up or change your home or small office network
This computer belongs to a network that does not have an internet connection
(This is exactly as per PC Projects by Kyle Macrae page 149).
I was prompted to make a Network Setup Disk which I did on FDD (also on CD as Comp 5 does not have FDD).
These (Comps 5 and 3) seemed to go through smoothly.