Run regedit32, and then follow these steps for NT Workstation or NT Server:
  1. Locate HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Rdr\Parameters
  2. Click Add Value on the Edit menu.
  3. Add the following:

    Value Name: EnablePlainTextPassword
    Data Type: REG_DWORD
    Data: 1

  4. Click OK, and then quit the Registry editor.
  5. Shut down and restart NT.

You can find this information in Microsoft's Knowledge Base article Q166730 on your TechNet CD-ROM or on the Web, http://www.microsoft.com/kb.