weird problems. urgent

i am facing this weired problem ….

i am windows nt netwrok setup…

server gives out IP address automatically….

k now…

all systems have to accept the address….

BBUT BUT ….. when the login screen comes….
i enter the passwrod…..

it says could not find the name….
and OK | CANCEL buttons are tehre

i press OK …. then i moves in….

in Network neighbourhood….
i can see only my PC and nothig else !

i try to ping server addres…. rewuest timed out…..

neither can the server ping anything….

ping also does not work

why ??? plz tell me ….

bye