Changing Computer Name in WinNT

I am having trouble changing the names of my workstations in Windows NT. When I change the name, the computer is no longer reconized by the PDC and is not allowed to log onto the network. I know I am missing a step somewhere, I just don’t know what. I have enabled DHCP, DNS and WINS Addressing. I need to change my computer naming convention and still have my users login the next morining. HELP