I recently installed 10/100 cards in my network (WINNT4 peer to peer workstations) and a Switch (100MB). The network I have is based on TCP/IP for there is also an ADSL gate to the Internet.
All computers have TCP/IP and specific IP (local 192.168.1.x) addresses.
The thing is that the network sometimes starts good, but in an hour or so one or more workstations don't have access to the network anymore. I can't find the reason for it. Cabling etc. seems tobe ok (could it be tested....). switch and cards are new.