Instructables

Permanently erasing data from your computer

Picture of Permanently erasing data from your computer
Did you know when you delete a file on your computer it's not really gone, even when you empty the recycle bin? If you going to sell/donate your computer, these files can be recovered simply, and even using free software (see pic below). In this instructable I intend to show you how to save your data from being recovered using free software, and the only thing you might have to buy is a blank cd.
 
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Step 1: Before we start...

There are three main ways you can erase your data:

1) Nuking the hard drive:
Is where you use a cd-rom to remove all traces of ANYTHING on your computer, including Windows. This means that you will not be able to boot into Windows after nuking, so you will have to reinstall windows (unless you specified when selling). This way is probably quickest.

2) Shredding your files:
Is where you haven't yet deleted the file, and you shred this one file instead of deleting it.

3) Erasing Free Space:
Is where you remove traces of things you may have previously deleted. This keeps your operating system.

Step 2: How does it work?

When you delete a file on your pc it isn't really gone, your computer has simply forgotten where it is stored, and thus cannot access it. The way you can remove the forgotten file is to overwrite where it is written on the hard drive. The way 'Erasing Free Space' works is it creates a random data file (or several) that is very large, to fill up the rest of the free space on your hard drive. Once there is no free space left, the large file is deleted normally, overwriting previously deleted files.
octavian2343 years ago
The best way to destroy data from your harrdrive is to burn it
iisjman07 (author) 5 years ago
Your BIOS is not set to boot from cd. You can follow this guide:

http://www.hiren.info/pages/bios-boot-cdrom and it should be similar on your pc
usernaming5 years ago
This is not working - I made the CD but when I turn my computer on it boots windows. Please help! Thanks
mrmath5 years ago
It may be worth noting that while all of these methods will work for the average Joe user, police and law enforcement officials may (or may not) be able to recover data after these or other techniques. (I'm not saying they can for sure, just that they might be able to.)
iisjman07 (author)  mrmath5 years ago
Shredding files and shredding free space doesn't always work 100%, but nuking a drive (even just doing a quick erase) makes it physically impossible
I was hoping your idea of nuking would include the literal definition - I know a few incredibly paranoid people who when it came time to upgrade to a new computer would take the old motherboard, hard drives, RAM (and any components with memory), and an old cruddy microwave. I'm sure you can imagine what that entails. Totaling an HDD is actually a rather reasonable idea if you want to upgrade to a higher capacity drive. Simply clone the old onto the new (or perform a file transfer if there are no system files on it), and take apart the old drive. The disks are great Instructables materials...Tesla turbines spring to mind immediately :-P
Heh I should have mentioned to only do either if you don't want to install the older drive into an enclosure...I brilliantly bought a nice SATA enclosure, installed a new HDD, and after a few distractions absentmindedly found myself opening the old drive while on the phone - I apparently had just grabbed the closest thing to me and decided to open it up after a service put me on hold. Needless to say, I was very, very glad I'd transferred the files to the new drive instead of my original plan of just installing the old into the enclosure first....
hg3415 years ago
have you heard of wipe disk i dont think its free but people tell me its the best it rewrites the whole disk to 1's or 0's
lemonie5 years ago
Repartitioning is pretty effective. But I guess it depends upon how paranoid you are about people making a lot of effort to recover your data. L