thanks again for previous aid.
'I didn't do anything, Olly'. Well, only, as I was going away for a few weeks, I unplugged my two XP boxes (a thunderstorm blew out my modem once). Putting back all the wires later, the main box won't make a LAN connect to box No.2. Box 2 seems OK, but when I try to access its files from box 1, the message 'A network cable is unplugged' comes on the System Tray. Whatever I try, the pesky red cross stays on the LAN icon.
I got & fitted a new cable. No good. No connection, so can't reload the LAN setup. Software, hardware, or idiotware - any ideas? - Gorila.