Change Login Auditing Option

USE [master]
GO
EXEC xp_instance_regwrite N'HKEY_LOCAL_MACHINE', 
   N'Software\Microsoft\MSSQLServer\MSSQLServer', 
   N'AuditLevel', REG_DWORD, 0 -- None (Neither successful nor failed --logins will be audited.)
GO
EXEC xp_instance_regwrite N'HKEY_LOCAL_MACHINE', 
   N'Software\Microsoft\MSSQLServer\MSSQLServer', 
   N'AuditLevel', REG_DWORD, 1 -- Successful Only  (Successful logins will --be audited, but failed logins will be ignored.)
GO
EXEC xp_instance_regwrite N'HKEY_LOCAL_MACHINE', 
   N'Software\Microsoft\MSSQLServer\MSSQLServer', 
   N'AuditLevel', REG_DWORD, 2 -- Failed only ( Failed logins will be --audited, but successful logins will be ignored.)
GO
EXEC xp_instance_regwrite N'HKEY_LOCAL_MACHINE', 
   N'Software\Microsoft\MSSQLServer\MSSQLServer', 
   N'AuditLevel', REG_DWORD, 3 -- Failed & Successful (Login will be --audited regardless of success and failure.)
GO