How to identify the SQL Server Start/Restart Date & Time ?

1. When was the SQL Server Service Started ?

SELECT agent_start_date FROM msdb.dbo.Syssessions WHERE session_id = (SELECT max(session_id) from msdb.dbo.Syssessions)

SELECT login_time from sys.dm_exec_sessions where session_id = 1

SELECT min(login_time) FROM Master..sysprocesses
-- SQL server 2008 only
SELECT sqlserver_start_time FROM sys.dm_os_sys_info;

SELECT login_time FROM Master..sysprocesses WHERE spid = 1

2. When was the TempDB database Re-Created ?
SELECT create_date 'SQL Server Started at' FROM sys.databases WHERE [name] ='tempdb'

GO