Have a look here Mark, it has some trobleshooting tips and guides on how to network using different methods :
http://www.practicallynetworked.com/support/troubleshoot_index.htm
I have only done them as either PC to PC using internet connection sharing or via a combined modem/router so I am not sure what happens with a modem, switch, and hub setup but I would have that it was similar.
Does the hub have DHCP enabled, that should assign an IP to each PC and I dont think that you want proxy settings used.
I assume that in your network connections it has set each one up as MSHOME or WORKGROUP, either is ok but they both must be the same and check that TCP/IP is enabled on both LAN connections too