Int 21 Fn 5F86  - Lantastic - Disable Account                              [N]

   AX = 5F86h
   ES:DI -> ASCIZ machine name and password in form "\\machine\password"

Return: CF clear if successful
   CF set on error
       AX = error code

Note:  must be logged into the named machine and concurrent logins set to 1
     by NET_MGR.  Requires system manager to re-enable account.