How To Completely & Securely Erase Your Hard Drive [Windows]

Take a moment and think about all of the sensitive data kept on your computer.  Account passwords, addresses, phone numbers, access to bank accounts and other financial services, and maybe even your social security number.  Almost every aspect of your identity is kept on this little machine.  Now imagine you want a new one.  So, you go out and buy a shiny new laptop.  What do you do with the old one?  Just toss it, right?
Wrong!  If you just throw out your old computer, all of that personal information is still available to any tech-savvy thief.  Merely deleting a file in the traditional fashion will not truly “delete” it.  With a few techniques, a file sent to the recycle bin and emptied can be recovered if the deletion was recent enough.

So how can you erase a hard drive completely?  Well, there a few techniques that anyone can employ to protect their identity.
Disclaimer: Please keep in mind that the following software and techniques will ERASE your hard drive and you will not be able to get your data back.  That’s the whole point.

Formatting

Most people’s first instinct would be to just reformat their drive to get rid of data.  But there are all sorts of formatting that can be done.

First, you can perform what is called a high level format.  Sometimes, this is referred to as a quick format.  This method is not secure seeing as it only erases the boot sector and partition table, thus leaving all of the other files intact and accessible through purpose built software.
There is also low level formatting, referred to officially as “disk reinitialization.”  This process goes through your disk and sets values to zero and will erase a hard drive completely.
For more advanced users, you can also change the number of passes that the format goes through.  The more passes, the more secure it will be because the format goes through the disk the specified number of times and writes over the information with junk.
As you would expect, more passes take more time, but more passes means your data is better scrambled and harder to recover.
This process sounds like it would do the trick, but there are some catches.  If you use a different file system than the one used to originally format the disk, or if you have multiple partitions, not all of your data will be thoroughly erased.
Thus, formatting the disk is not the preferable way to really, securely erase your data.  Instead, there are some freeware tools you can use to make sure your information is gone.
If you do want to go the reformat route, MakeUseOf already has some good articles on how to do that here and here.  You may have to use your OS disk, or software that came with your drive to perform the format you want.

Darik’s Boot And Nuke

If you checked out Varun’s article linked above, you’ll notice he mentions Darik’s Boot and Nuke.  Let’s take a closer look at that tool.
DBAN, as it is shortened, is a nice little application that lets you completely erase your data.  You can download it for Intel/AMD machines and Apple Power Mac machines by clicking “Downloads” at the top of the home page.  You should see the following.

Download the ISO for your system and burn it to a disk.  Next, pop the disk into your hard drive and boot from it.  This may require you to press F12 at the BIOS screen (the first screen you see when your computer boots up) and choose to boot from your CD/DVD drive.  After the CD boots up, you should see the following.

Hit Enter and the program should boot a few things up before settling on the next screen.

Hit Space when the arrow is pointing at the disk you want to wipe and hit F10 to start the process.  The process will start and you should see something like this.

Let it run through the whole process and you should get a screen letting you know the process was successful.

DBAN is easy and performs well.  There are other options to get rid of your data for good.

Get Physical

The absolute best way to make sure your data is completely gone is to just destroy the drive.  Clearly, this is only an option if you are going to dispose of the drive afterwards.
There are a few ways to go about this.  You could get some high powered magnets and wipe the drive a few times with them.  This scrambles all the data that is written magnetically on the disk.
Another option is to wail on the drive a few times with a hammer.  Please remember to wear proper safety accessories such as safety glasses when using tools.
Finally, you can always take the drive apart to make sure the disk gets completely demolished.  To do this though, you will probably need a special T9 torx screwdriver.  Or, you can try to simply pry the thing apart, but please, as before, use proper safety measures.
On top of making sure you completely sure your information is gone, this can work out to be a good stress reliever.
Now you have the tools to make sure your identity is safe if you want to get rid of an old hard drive.  Know of any other tools or methods?  Let us know in the comments below.