When you delete a file from your hard drive, it's not completely erased. Similarly, when you format a hard drive, the data can sometimes be recovered.
If you give an old PC to someone else, or donate it to charity, it makes sense to complete destroy any data on your hard drive. You certainly don't want your sensitive financial information to be recoverable under any circumstances. With a simple floppy disk and free software, you can have that piece of mind.
We now recommend DBAN as a simple and secure way to completely erase your hard drive. On Windows XP, here is what you do:
Important: Going through these steps will completely reformat your computer's hard drive! All data will be lost, including the operating system and programs. Make sure you have a backup of your documents before proceeding. You will need an operating system (i.e. Windows) CD in order to make this PC functional again. This process will also destroy any "recovery" partitions put on the hard drive by your PC vendor.
(Note: you can make the DBAN nuke floppy on any computer. It doesn't have to be on the one you want to erase)
1. Download the DBAN zip file and save it to your desktop.
Alternatively, you can grab the latest version from the DBAN website.
2. Now you need to unzip it. In XP just double click on the zip file (for other windows versions you may need to use a free unzip application like Winzip).
3. A folder will open with several files. Double click on dban-1.0.6_i386.exe and a windows message will pop up. Select extract all and follow this process through to the end.
4. Now another folder has appeared. Double click on the same .exe file named above (it now has a little floppy icon).
5. Follow the onscreen instructions. You will need to insert a blank floppy into your floppy drive at this point. If it prompts you to reformat the floppy first, please do so.
After the process is complete your "nuke" floppy has been created. You now need to put this nuke floppy into the floppy drive of the pc you want to erase. Start the pc WITH THE NUKE FLOPPY ALREADY INSERTED. The pc needs to be set to use the floppy drive as the first boot device.
If the PC is set to boot from the floppy drive, you will see the nuke floppy load into memory.
If the PC does not boot from the floppy, you will need to change your BIOS options. Typically, you would hold down the delete key as your PC starts up to get into the BIOS options. The boot sequence is usually on the first page or under advanced bios features. There should be onscreen intructions at the bottom that will explain how to change the settings. Once floppy drive has been made first boot device save changes & exit (usually by pressing F10 again look at the onscreen instructions).
At this point, the nuke floppy should now be loaded into memory. Continuing from this point foward will irrevocably erase all data on your hard drive.
At the prompt type PRNG then hit Enter. Depending on the size of your hard drive the process will take from 1 to 12 hours. At the end an onscreen message should confirm if wipe was successful.
It will also ask you for another floppy to save a log file. You do not really need to worry about saving the log file although you can if you wish. It is used for troubleshooting by experts and can be useful if the wipe failed for some reason. An expert would analise the log and tell you why it failed (maybe physical damage on the hard drive, things like that). I have never bothered saving the log file.
Your hard drive is now completely clean of any data.