T.J. Hooker CastI’m sure many of you have considered donating your old computer to a school, church, or other non-profit organization. While I encourage you to do so (tax writeoff!), you need to be aware of the potential danger to your personal security if you do so.

Preparation ends at deleting personal files? Not so much…

Of course, the first thing that comes to mind when donating or trashing an old computer is “I’d better delete my files”. While this is obviously a splendid idea, make sure that you are making every effort to protect your privacy by understanding what ‘delete’ means.

In the Windows world, when you delete a file or folder from your computer, they are essentially “marked for deletion” - think of it as taking the label off of your videocassette (ah, memories…) with your favorite episode of say, ‘Falcon Crest‘, but not actually re-recording over it until ‘TJ Hooker’ is on later during the week.

When a file is marked for deletion, it tells the operating system that “this block is available if you have anything to write here”. However, your OS may have plenty of other blocks to write to before writing something in this newly available block (in keeping with our example, you have plenty of new blank tapes to record “The Hook” on, so you decide to use those first, instead of compromising video quality on a pre-used cassette). So in essence, your data is still there on your drive, ready to be restored at any time; a number of utilities exist, free and payware, with the ability to restore your deleted data quite easily, and by computer-novices.

Case in point:

I worked for a large corporation as a desktop support agent. One of my younger colleagues forgot to back up a computer before loading a new cloned image on the PC, essentially overwriting all the data from the previous configuration.

Or, so he thought.

In an act of desperation, I ran a Norton file recovery and undelete command on the drive, and was able to restore EVERY file from the previous configuration (probably saving my young friend his job!).

Things you can do to help yourself:

  • Get the help of a techno-nerd friend to securely delete your data. Entice him/her with pizza and gift certificates to NewEgg.com if necessary.
  • Use an encrypting container to house your sensitive data (for example, CryptArchiver Lite or CryptainerLE, There are many others).
  • Delete your files using a secure erase program (see below)
  • Defrag your hard drive often, especially after you uninstall a lot of software, or delete large amounts of data. This will overwrite the empty blocks quicker (if the amount of data surpasses the point on the drive where your deleted file was located). This is not a surefire method, but it will enhance your performance in addition to latently increasing the chances you are overwriting your ‘marked’ files.
  • If you are trashing your computer and no longer need the hard disk, remove and smash it with a large hammer. Seems a bit barbaric, but it is extremely satisfying. If the hard drive is sizable enough, consider buying an external USB enclosure and using it as a backup drive.

Giving can be a wonderful thing; it gives you that warm-fuzzy feeling when you’ve done something nice…don’t let one second of that familiar “oh…no…” moment (you know what I’m talking about) ruin your “feel-goodiness.”

You’ve done something nice, enjoy the feeling!

Secure file erasure:

File/Folder/Disk wipe:

Recommended reading:

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Tim Fehlman