If you have an existing installation of SQL Server, you can choose to upgrade it to SQL Server 2005 instead of installing a new instance. SQL Server 2005 supports direct upgrade paths from SQL Server 7.0 with SP4 and SQL Server 2000 with SP3 or later versions. Table 8-7 lists the versions of SQL Server and the possible direct upgrade path to the corresponding SQL Server 2005 edition. Before upgrading from one edition to another, you should always verify that all the functionality you are currently using is supported in the edition being upgraded to.
Table 8-7. Supported Upgrade Paths to SQL Server 2005
Supported Upgrade Paths
SQL Server 7.0 Enterprise Edition SP4
SQL Server 2005 Enterprise Edition
SQL Server ...