Detach the database files from SQL Server 2005 and attach to SQL Server 2008 Server
Execute the below command to update the index and table Statistics in the newly attached database
It is recommended to execute update statistics separately for each table with full scan as given below
Execute the below command to rest all the counters DBCC UPDATEUSAGE('
Change the Database Compatibility Level as specified
Go to Database Properties à Options à Compatibility Level to à SQL Server 2008(100)