How to securely erase your hard drive

Are you planning to recycle, donate, gift, or sell your computer?   Before you do this, you should think about the data on your hard drive.  There is lots of personal information on your drive that could be used in a harmful way if it were to fall into the wrong hands.  
A colleague of mine has purchased numerous hard drives off of eBay and found data on them when he installed them.  There are man people who purchase used hard drives with the express purpose of gathering data from them.  So what is one to do?  
You have a few options.  

  1. Remove the hard drive completely.  If you are disposing of the computer for re-cycling, this is the best option.  Simply put the hard drive on the shelf and you will have access to the data if you need it.
  2. Remove the hard drive and replace with a new one.  This is similar to option #1, but adds the cost of an additional hard drive to your gift or donation.
  3. Securely wipe the hard drive.  This is the best option.  Make sure you have the operating system (i.e. Windows) otherwise the gift or donation is useless :).  The rest of this article will describe the best tool that I've found.

Securely wiping the drive:
WARNING - None of these tools should NOT  be used with solid state drives (SSD). 
Simply formatting the drive with standard tools will NOT erase the data.  It will simply clear out the index.  This is comparable to leaving all the books in the library but getting rid of the card catalog.  There are tools available which can recover data from accidently erased drives.   Here are some tools you can use to erase a drive

​Darik's Boot and Nuke (DBAN)
Darik's Boot and Nuke (or DBAN) is a bootable CD that will walk you through wiping a drive.  It is available for download at
There are several options inside the program.  Do not use the "Quick Erase" option as this is the same as doing a standard format.  The DoD 3 pass is sufficient for most uses. 
Once you use this utility, the drive will be completely erased, so make sure that you have all the data you want backed off of the drive.