Maybe you are giving away your computer to one of your friends/family, or perhaps you are lending your hard disk to a friend. You don’t want them to be able to get your data and see what you had stored on your hard disk, so you delete everything and scrupulously make sure that you cannot see any file and folder within Windows Explorer. Feeling satisfied, you lend it away only to realize later that files can be retrieved even after you have deleted them from the hard disk.
So what should you do to ensure that the files were “really gone” and could never be retrieved. For starters, never say never! As long as you don’t dismantle and physically destroy the hard disk, your files can be retrieved (and you thought recovering files after an OS install was impossible). That being said, chances are you won’t have to worry about forensic experts trying to get super secret formula X from your computer.
With a little care, you can be pretty sure you would be able to dodge the attempts of your overly geeky friend. Here’s how.
Format, don’t just “quick format”
First off, when the operating system is running, you cannot be sure if any files are actually deleted. At the very least, you have to format your hard drive. So when you decide to do so, don’t save time by doing a “Quick Format” – it doesn’t delete files, use the other option and perform a complete format which will erase your hard disk completely.
You can achieve this by booting from Windows disc and choosing the appropriate option. Linux users can boot from one of the live CDs and use the fdisk utility to format the hard disk
This should take care of any fears of data recovery by novice users
Securely delete the files
You can step it up a notch by securely deleting files from the hard disk. A secure delete not only deletes the files, but writes random data onto your hard disk as well, making it extremely (I mean EXTREMELY) difficult to get the files back.
If you are erasing your hard disk completely, you can use Darik’s Boot and Nuke, securely deleting data is the sole purpose of existence of this bad boy. Boot DBAN and let it do what it does best.
If on the other hand you want to securely delete files from a USB stick or external hard drive you can try previously mentioned and very useful Eraser. It integrates with Windows shell and lets you perform secure deletes from the context menu.
These methods would pretty much have you covered, but be warned: an adept professional may still be able to retrieve files although these methods would still give him a pretty tough time.
Do you know of better software or tips that you use for similar purposes? Mention them in the comments and share with the world!