domain name register

Hi

Our company has a PDC and BDC with several other servers. The problem is that everytime I shut down the BDC, all the workstastions and servers lose connection to each other. So I ran nbstat -c (suggest from news group) and here is the result
Name Type HostAddress
C2 <1C> GROUP 10.1.1.2

C2 is my domain and 10.1.1.2 is my BDC.
So somehow the domain name registered under the BDC not PDC that why we loose network connection when reboot the bdc.Is there a way to fix this problem? By the way WINS, DNS, DHCP is on the PDC
and both PDC and BDC are in the same room.