problem with win98 network tcpip with ip automatically

hello i have a lan with few pc with winxp and win98se
the pc's with winxp the have no problem
but the pc's with win98 have 2 problems
1st
one pc with OS win98 from the icon network neiborhood "can see" all the
computer except it shelf
2nd
another pc CANNOT see any computer when i use ip andresses automatically
When i change the network settings all the lan with ip "concrete" like
10.0.0.xx everything works perfect
unfortunetly i have to use ip automatically can u imagine why one computer
of all doesnt see the lan with andresses automatically
??
I unistall the lan card and i installed again but nothing change



thnks