After running the latest hotfixes (long list as usual!), the NT 4.0 machines on the SBS 2000 network couldn't connect. We tried heaps of things like uninstalling the hotfixes, restoring a previous System State ...
The last things tried before a reboot was, and that worked was either:
1. Open the [Properties] for the local network adapter on the server. Select the [Authentication] tab and uncheck the [Enable network access control using IEEE 802.1X] ...
or:
2. Patch the registry per a problem resolution in the Microsoft KDB in respect of NT 4.0 BDC authentication via LSA on a Windows 2000 PDC as follows:
1. Start Registry Editor (Regedt32.exe).
2. Locate the RestrictAnonymous value under the following key in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Lsa\restrictanonymous
3. On the Edit menu, click DWORD, type 0 in the data field, and then click OK.
4. Quit Registry Editor.
Restart the Windows 2000 domain controller.
** I checked some other server installations, and the value was usually 0 (one of them had 0x1).
If this works for you, please let me know, especially if you are able to try "one at a time" ...