Today I had a friend on Facebook ask if I knew of a DMV or DMF that provided the date upon which the SQL Service was last started. What I use instead in any of my queries is the create date of the tempdb database. Why? Well simply put, tempdb is recreated each time the SQL Server service is started. Therefore, by querying sys.databases (or sys.sysdatabases) for the creation date of tempdb you can determine when the SQL Server service.
Either of the following queries work in SQL Server 2005 or 2008: