In 2002, two MIT students bought 158 used hard drives and recovered 5,000 pieces of delicate information such as credit card numbers, medical records, and financial information. They also found porn and emails. Lucky for the previous hard drive owners, the MIT students had no intention to use what they found. Instead, they were conducting a study to see how many people (or companies) took precautions before releasing their hard drives back into the wild. Only 12 drives were clean.
So what are you doing to do with your computer? You have plenty of those old photos of your party days; you've saved all your card information for your online shopping; and you've filed your taxes on this computer for the past 3 years. Now is time to donate it or to sell it. So you take your time to back up and delete all of your personal files so no one else will access them. You're not like those 158 people who left their hard drives out to dry.
"Deletion" is Window's Broom Closet
Don't feel secure yet. "Deleting" isn't a true concept. Believe it or not, simply deleting files will not permanently erase them from your hard drive. Instead, the information simply goes into your Window's broom closet, just in case you actually want that file again so that advanced users could easily recover the data.
Windows does, however, erase the "short-cut" to your information. So a typical user won't be able to access that information, but that doesn't mean that it's gone. The information could still be recovered.
It's no wonder that people freeze and then take a hammer to their hard drives. How else could you be safe? Wait; don't throw your hard drive in the fire yet. Besides, you want a good return on it, don't you? Here are two things you can do to prevent personal data from being recovered by unwelcomed hands, without going to extremes.
Formatting Your Computer: Secure?
Formatting hard drives is a common way to make data unusable. But alas, reformatting may "cover up" the data, but it is still there and can be accessed by hard drive recovery experts. 60% of the MIT student's used hard drives were formatted, but information could still be retrieved. However, this may be a great option for you, depending on what kind of information you have on your hard drive.
"Wipe" the Drive
A much more secure way to eliminate all the data on your hard drive is to "wipe" it. You don't need a professional to do it, either. Free programs like Darik's Boot and Nuke are available.
A hard drive "wiping" program overwrites all of the previously stored data with the numbers zero or one. Before you begin, remember that you will have a completely unusable computer after you're done. You'll then need to reformat it and re-install programs. Though it may seem like a lot of trouble, one wipe may not be enough. The more times you overwrite the disk, the less likely the data could be recovered. The government wipes disks 6 times for medium security level.
Hire a Professional
If all else fails, or you don't feel that your efforts will be enough, sending your drive to professionals to permanently wipe it is a great option. It's better than leaving personal information around to be read. But no matter what you choose to do, taking some precautions is better than taking none.