To uninstall SQL Server 2008, select Control Panel Add/Remove Programs. If you wish to remove the entire instance, select Remove. If you wish to drop some of the services for the instance, but not all of them, select Change.
You can also use the Add/Remove Programs feature of the Control Panel to add or drop SQL Server components from an existing instance.
When you uninstall Reporting Services, you need to do manual cleanup on some items, as described in this section. Before the uninstall, though, you need to gather some information. Make sure you know which databases are being used by this instance of Reporting Services. You can obtain this information from the Reporting Services Configuration tool. Discover which directory this instance of Reporting Services is installed in by running SQL Server Configuration Manager. You also need to discover which directory the Reporting Services usage and log files are using. To do this, run the Error and Usage Report Settings, in the All Programs Microsoft SQL Server 2008 Configuration Tools section, as shown in Figure 2-8.