Cannot delete old back up files/folders

When I had Windows Live One Care, it backed up my files to an external hard drive.  I have not had the WLOC for some time and I now want to delete all of those old back up files but it will not let me.  All files are marked "Do Not Delete".  I have gone into the file properties and unchecked the "Read only" box, but still cannot delete them.  How do I get rid of these files?

See: http://social.microsoft.com/Forums/en-US/onecarebackupandrestore/thread/f0281206-ed0b-474c-8541-cc50843e5be2

-steve