To uninstall Kentico CMS from your computer, open Start -> Control Panel -> Add/Remove Programs. Choose Kentico CMS and click Uninstall.
The uninstaller will delete all files created on your computer except the deployed instances of Kentico CMS - it means that the database and the Web sites will not be removed and you have to delete them manually.
Page url: http://devnet.kentico.com/docs/devguide/index.html?uninstallation.htm