type NT SERVICE\TrustedInstaller in "Enter the object name to select" text box
http://www.askvg.com/guide-how-to-restore-trustedinstaller-as-default-owner-of-a-file-or-folder-in-windows/
http://www.askvg.com/add-take-ownership-option-in-file-folder-context-menu-in-windows-vista/