To find out your version of SQL download/install/open Microsoft SQL Server Management Studio Express then click New Query
Paste the below code in the query pane on the right
SELECT @@VERSION
SELECT SERVERPROPERTY(‘productversion’), SERVERPROPERTY (‘productlevel’), SERVERPROPERTY (‘edition’)
and click Execute
In the results window it will display the version, Service Pack, and edition.
For older versions refer to the command and chart on the Microsoft KB 321185.