Removing Multiple Instances of SQL Server 2000
When you remove a default or named instance of Microsoft® SQL Server™ 2000, the data files and registry keys for that instance are deleted. Tools cannot be removed until all instances of SQL Server 2000 have been removed from a computer, because the tools are shared among all installed instances.
To remove a single instance of SQL Server 2000, or to remove all installed instances, see How to remove SQL Server 2000 (Windows).