This registry hack allows you to take full ownership of files or folders as explained in this article.

Taking full ownership is for files and folders that you can't open, delete, move or rename. The TrustedInstaller, part of User Account Control protects crucial files so that even Administrators can't open, delete, move or rename. We've also seen this happen with files on external or secondary hard drives that aren't system files including, and especially, photos.

If the registry hack fails to work, then see How-To Take Full Ownership of Files & Folders.