How do I delete Windows 7 files/folders from an old hard disk I no longer use for booting from. I cannot delete these folders: Program Files, Program Files(x86), ProgramData, Windows. I get this error msg when I try to delete the above: "You need permission to perform this action. You require permission from TrustedInstaller to make changes to this folder" Also I cannot delete any protected operating system files/folders, it says I need permission from the administrator. I am the administrator and there are no other user accounts on my computer.