Restore SQL Server 2005 backup db on SQL Server 2000
Solution 1:
Not possible.
Here is an MSDN forum post that describes how to create scripts from the SQL 2005 database that you can run on a SQL 2000 server that re-create the database, including data.
Note that if all you have is a 2005 backup file, you'll have to restore it to a 2005 instance before you can create these scripts.
Solution 2:
Sorry, you can't attach a newer version database to a older version server.
Try a DTS copy job from 2000 to 2005. http://msdn.microsoft.com/en-us/library/ms345120(sql.90).aspx
Solution 3:
I have a blog post that explains the various errors you may see when trying to do this. See Msg 602, Level 21, State 50, Line 1.
Back in my SQL Q&A column in TechNet Magazine in August 2008 I explain the database upgrade process and how it changes the physical structures of the database, bumping the physical database version as it goes, so previous server versions can't use the newer database versions.
Hope this helps set some background.