Guide to wiping your hard drive.

Let me take you back to the distant and sunny times of May 2009; some clever researchers at the BT Security Centre bought hundreds of second hand hard drives off eBay – stick with me.

Now say for example you are a defence company called Lockheed Martin who, when not developing terrifying exoskeleton technology to allow soldiers to carry 200 pounds of extra gear across a battlefield, stick to the no less scary business of blowing stuff up, from the air.

The researchers purchased the previously mentioned hard drives off eBay. Amongst the normal sordid details of fraud, affairs and company budgets, there were test launch procedures for Lockheed’s Terminal High Altitude Area Defence.

It’s a ground-to-air defence system that shoots down other missiles; surely no-one could be interested in that?

You might not have any launch codes, but you probably have bank details, passwords, info about your job, home and family. In the wrong hands this is all someone would need to really mess up your day. If you sell, exchange or donate your PC make sure it’s been wiped first.

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A hard drive is where your computer permanently stores its data. Inside the hard drive is a disc (note the spelling) which looks a lot like a CD. This is the spinning platter, and if it’s a cheap drive, old or just a bit cranky, it might be what makes that whirring noise in your PC.

Anyway. The arm over it, is called the actuator arm and it encodes data in binary onto the disc, using the read and write head.

To wipe your data you need to overwrite what’s already on there with new strings of binary.

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Deleting files and users is not enough; at the very least re-partition your hard drive, erasing what was on there before.

Insert your Windows disc or factory settings restore disc, then chose to delete the old partition, and over write it with a new one. This will leave a brand new Windows, but to law enforcement your data will be recoverable.

There’s plenty of free software that will kill your drive for you. Darik’s Boot and Nuke (DBAN) is one of the best, download it, burn to a bootable disc or USB. Then when the disc is booted it will strip your computer of everything, turning it into a large paperweight inside a few minutes.

Word to the wise, whatever you put it on, CD, USB etc label it well – there is no way in you want to let DBAN near any computer that’s still useable as it will nuke any hard drive. You have been warned.

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• Pick up a screwdriver.
• Unscrew and open the drive casing.
• Put down the screwdriver.
• Pick up a hammer and get a bit medieval on it.
• Rest safe that no-one but MI5 are going to be able to recover your data.

Note: There are machines called de-gaussers which will magnetically scramble any data. They cost a few grand though; maybe Lockheed Martin should invest in a few.