So the old Apple Airport basestation is gone. It was just too unreliable and kept overheating and cutting out. It's been replaced by a new one from Netgear.
The Powerbook (of course) just worked first time with the new basestation, as did the two Linux machines. It was a different story with the Windows (actually Win98SE) machine tho'. And an hour or so of fiddling last night didn't seem to fix it.
The problem seems to stem from the fact that the new basestation doesn't contain a DHCP server like the Airport did. The Windows machine seemed happy enough to get DHCP info from the basestation but is too lazy to look any further for it. Even tho' there's another DHCP server on the network (in the ADSL router).
So last night I played with giving it a fixed IP address and DNS servers. I managed to get it pinging the ADSL router, but no further. Looks like I'll be spending a large part of this morning deep in the world of Windows support web sites.
Did I mention that I hate Windows?