You may have thought this is some Cnet product tech support. It's not. That's over at cnetusa.com.
I have 10 computers, one a server, networked to a Stack II switch and a DSL line. A piggyback Stack II hub is running two more computers. All connections are cat5 cables, well under lenth liments, and work on the Stack II system. No problems except they are 10 meg connections. When I install the cnet switch, which runs at 100 meg, some computers perfectly access the network and the web while others say "network cable unpluged", or will access the web only and not see other computers. I am sure no cables were unpluged! The machines run Windows XP, 2000, and NT on the server. The operating system seems to make no difference as both XP and 2000 machines have problems. The XP server is fine.
I also tried to replace the Stack II hub with a new 100 meg hub, and again one machine out of two accessed all fine, but the other would not connect.
I am lost at this point. This was suposed to be a plug an pray swap. HELP... Any sugustions?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic