I went ahead and added the same computer again.  I was then able to delete the other computer which had the files on them. 
I have a new Dell computer (XPS 8500) that I purchased in Aug 2012.  Upgraded from Windows 7 to Windows 8 in October.  For the past six weeks when I log into my Dell Data Safe account I cannot purge any files, do any backups, or change the settings.  I keep getting an error message that the computer is not on line.  I don't know if upgrading to Windows 8 caused this problem or not.  How can I be on-line but not the computer.  Is there a way to fix this?  I am about ready to go with Windows 8 SkyDrive and drop Dell Data Safe.  But I would like to purge all of my files on Dell Data Safe before doing so.   
Dell Data Safe Says Computer Not On-Line