Can’t see BDC

I have an NT network with a PDC and a BDC. Every morning, most of the network cant see the BDC. The PDC is running WINS and DHCP. IF I restart both Servers I can ususally get it to work again. There are no errors in the event log. I have tried reinstalling wins, deleting the wins database, installing wins on both servers, installing wins only on the BDC and still have the same problem. I can ping the bdc by both IP and Name. Help!!