People give their old PCs away to family members, charities, and some end up at the local PC repair shop without ever being properly wiped clean. My first job was working for a company called New Life Computers. We received donated computer systems from companies and individuals that would later be donated to people with disabilities. Before we could donate the computers, we had to insure that all the software was removed, and a fresh opperating system was installed. You would be surprised what we found on some of those hard drives, thank goodness our employees were trustworthy.
Remember that everything stored on your PC is on the Hard drive. Computers that came from the state, or from large companies were usually clean, or at least they gave it the old college try to remove the data from the drives. You really have to know what you're doing in order to clean a hard drive of all its data, and then insure that the information can not be recovered. We found thousands of credit card numbers, pornography, love letters, you name it, that were completely recoverable on some of these drives.
Most people believe that deleting data and then cleaning out the recycle bin does a sufficient job. This is NOT the case however when you delete something in windows-it just marks it to be over written. There is also a misconception that formatting a Hard drive permanently erases stored data. This is also not true-a format just reconstructs the allocation table and checks the blocks on the disk but it does nothing actively to remove the data, it simply leaves it "unprotected". With both of these situations, if you have the right software you can recover data thought to be unrecoverable.
So, how do we erase this data on my hard drive for good? You can physically destroy the drive-but that's not as easy as you think and you would be amazed at what people can recover data from. There are cases where people have drilled holes in the platters and it could still be recovered. You can take it to a PC repair store that has a Degausser that removes all the magnetism from the drive leaving it useless for good, but this can be way too expensive to justify the price for the common end user. You can write Zero's to the drive with the utilities at the Hard drive manufacturer site and that will stop most people, but experienced users can still recover it.
If you don't want to destroy the drive, and are concerned about keeping your privacy here are two free programs that will totally erase data from your hard drive.
First is Darik's Boot and Nuke which is an application that you can install on a bootable floppy or CD Rom. Boot and Nuke uses several methods to wipe the data on your drive to an unrecoverable state. Click here to visit the home page of Darik's Boot and Nuke.
The second title is Eraser and Though this software is free, a $15.00 donation is encouraged. This software does a great job of sanitizing your hard drive by removing all magnetic and solid state memory. It does this by using several different techniques including "pseudorandom data overwrite" and techniques defined by the Department of Defense. Click here to visit the Eraser home page.
Once one of these procedures is performed the drive is ready to be given away or thrown out without fear of privacy invasion, fraud, or worse. Would you just throw away an old wallet with everything still in it? Of course not. So why would you give your PC away without making sure it wasn't clear of personal information? I've seen this many times repairing someone's PC that they were giving to their folks or have gotten from friends and these people made vary little effort to protect themselves and with that same amount of effort I probably could have taken them to the cleaners. You've read other articles in Fred's Head about being safe with the computer, but don't forget that your safety must continue when the computer is ready to be retired.