Look here:
http://support.microsoft.com/default.aspx?scid=http://support.microsoft.com:80/support/kb/articles/q157/8/15.asp&NoWebContent=1
Windows NT 4.0
In Control Panel, double-click the Network icon. On the Services tab, click Add and add NetBIOS Interface.
If NetBIOS Interface is already installed, confirm that there is a protocol binding to the adapter. In both Windows NT 3.51 and 4.0, you can check the protocol binding on the Bindings tab (in Control Panel, double-click Network). If no protocol is bound to the adapter, remove the current protocols, and add them back in.
If this issue continues to occur, follow these steps:
1. Uninstall the NetBIOS Interface, and then restart your computer.
2. Reinstall the NetBIOS Interface, reapply the latest Windows NT Service Pack if applicable, and then restart your computer.