The Upgrade Advisor Analysis Wizard examines your instances of SQL Server 2000 and SQL Server 2005 for issues that can prevent ...

The Upgrade Advisor Analysis Wizard examines your instances of SQL Server 2000 and SQL Server 2005 for issues that can prevent you from upgrading, or that can prevent your applications from working properly after upgrading.  If the wizard finds any blocking issues, you must fix them before you can upgrade.  The wizard does not modify any data on your servers. You can run the wizard as many times as necessary to examine your SQL Server components and prepare for upgrade.