You can uninstall Microsoft SQL Server 2008 R2 using Windows Add or Remove Programs.
1. Open the Add or Remove Programs from the Control Panel. Locate the Microsoft SQL Server and click on Change/Remove. A pop up will come out, choose Remove.
2. The Setup Rules will execute. Click OK.
3. Select the instance to uninstall. Click Next.
4. Select the Features. Since you are planning to remove everything, you can select it all. Click Next.
5. Setup will run the removal rules. Once done, click on Next.
6. The next page will show the verification confirmation before you can start to uninstall. If everything is confirmed, you can click on Remove. The removal progress will start.
7. Complete!
