Wednesday, 4 May 2011

Deleting your personal information before selling your computer

So you’ve decided to sell your computer, I guess you’ll be wanting to erase all your personal information before you let it out of your hands then?!

I'm going to assume that most of you are Windows users so this guide is tailored to it. Now you have two main options before you sell your computer, one is to completely erase the hard drive, the other is to only erase specific personal files securely. Both methods use free software available to download from the internet.....
As this is article deals with data deletion the following disclaimer is unfortunately a must – Any action you take as a result of this article is your own responsibility. I will not be held accountable for content on external links or any loss of data. Please check all your downloads with antivirus software. This is a guide and you are advised to research further if you have any doubts as to what these directions will do.

OPTION 1: Securely wipe the entire hard disk including the operating system.
This is the best option from a security point of view but this will erase ALL the information on the hard drive and will mean that the computer will be unusable until the new owner (or you) installs an operating system (windows, Linux etc.) on to the hard drive. This is only suitable If you are absolutely sure that you no longer need any data on the computer and that you can sell it without an operating system or you can install an operating system yourself.

1.) Backup anything you need to keep!

2.) Download (but do not open / run) Darik's Boot and Nuke ("DBAN") from:-
Documentation and screenshots can be found at:-

3.) DO NOT OPEN the file – Burn it to a CD or DVD - your going to use it as a boot disk.

4.) Put the CD / DVD in the computer then restart the machine.

5.) You should be presented a screen to select which type of erase to perform.(If not you may need to configure your bios to boot from CDROM first). For personal needs I'd suggest DODShort method would suffice but you should read the documentation for more information.

6.) When its finished your hard drive will be completely wiped.

OPTION 2: Securely delete personal information / specific files and slack space.
This option allows you to use an application called Eraser to securely erase specific files and folders.

1.) Backup anything you need to keep!

2.) Download Eraser from -
Documentation for eraser is included in the download and there is also a forum -

3.) Install Eraser

4.) Right click on the folder/file that you want to securely delete and there should be an option similar to “Erase with Eraser” - when you select this it will be securely erased and should not be able to be “undeleted”. More detail is contained with the Eraser documentation.

5.) Also use the “Erase File Slack Space” option in Eraser. This will ensure that any previous files deleted in a standard Windows method will also then be securely erased.

I hope you've found this useful.
As always, please feel free to leave a comment.
I'll update this with additional information if required.

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