I've got a couple of computers on two routers, of which one is used only as
a switch. No wireless components are used. However, one system doesn't
acknowledge that it has a network by that icon in the quick-launch bar that
indicates a LAN conneciton, and sharing doesn't work in both directions.
Surely there's a straightforward way to rip-out and replace the networking
configurations at both ends, such that it will actually share printers and
files over the LAN. I use Windows XP firewall on both ends.

I have network-accessible storage that seems to work OK from both ends, and
both ends have internet access through the common cable modem. However, the
two don't have normal sharing capability, and I believe that's because
something's configured incorrectly.

Is there any way to verify and remedy this?

thanks!