Given in your question and I'm probably wrong here anyway but I think your trying to say that you have Y2K as servers, Windows 9X as workstations and you ar running Novel Netware 4.11. Now the problem appears to be that the Win (X can't see anythingon the network but the servers can. Am I right so far? What has changed just before this happened?
But as a starting point I'd try reinstalling the Netware again on all the Workstations and then try seeing what happens.
AS far as network speed being down I can't see where this is coming from unless the servers arn't comunicating with each other in anything but a slow manner. Or is it that the server is only transmitting data slowely to each workstation?
A lot more detail here would help no end as it would give us a place to start.
Now as a guess after reinstalling Netware if things don't start working I'd go looking for some form of infection Virus trogan ect but without more infomation I don't know where to start.