No. The same database files cannot be used for both SQL Server 7.0 and SQL Server 2000 instances. SQL Server 7.0 databases can be upgraded to SQL Server 2000 databases, but after the database files are upgraded, they cannot be used by the SQL Server 7.0 instance. Note that this database upgrade is done automatically when a SQL Server 7.0 database is attached or restored to a SQL Server 2000server. In addition, there is no way to downgrade the database files from SQL Server 2000 files to SQL Server 7.0 files.