Serena, from North Carolina, asks:
I am looking to get rid of my computer, but I want to make sure that everything is off of my hard drive (banking info, etc.). How can I do this and be sure?
Serena, you are right to be cautious. Many people think that formatting a hard drive is the best thing to do in this situation. However, this still leaves behind traces of the data that you used to have on your computer, and undelete and data recovery tools can soon restore this information.
In 2003, students from MIT bought 158 used hard drives from eBay and other second hand sources. Credit cards numbers, financial information, data files, medical records, browsing histories, emails and more were all recovered from these disks, despite the fact that 60% of them were formatted before they were sold.
So, how do you make sure that your data is gone for good? You need to use a secure disk wipe utility. They used to be the preserve of government agencies, but now everyone can get a hold of software that will exceed or meet the Department of Defense standards for the secure deletion of data. Here’s how to do it with Darik’s Boot and Nuke, (DBAN).
1. First, make sure that all the data you want to keep is backed up and copied to another source, because once this process is complete, you will not be able to recover any data from your hard drive.
2. Download the free DBAN software  from their website. It downloads as an ISO file.
3. Next, you need to burn this image to a CD-R or DVD-R. It is important that you burn it as an image, and not simply burn it to a disc. To do this on Windows 7, right-click on the DBAN ISO file and select Burn disc image.
Now click Burn to start the burn process.
If you are using XP or Vista, you will first need to download an ISO burn utility. You can find a free one here. Once installed, you just right-click on the DBAN ISO file and click Copy image to CD.
4. Now that you have Darik’s Boot and Nuke on disc, you need to restart your computer and make it boot from your CD/DVD drive. Instructions on how to do this will vary depending on the manufacturer of your computer, but it usually involves pressing a function key during the boot up screen so that you can enter the BIOS settings screen and change the boot options to boot from the CD/DVD drive instead of the hard drive as it will be set to do by default.
Dell users should hit F12 a few times as soon as the computer restarts in order to get quick access to the one-time boot menu that will allow you to select the CD/DVD drive as a bootable option.
5. As soon as DBAN loads from the disk you created, you will be greeted with the options menu. For a default wipe, type autonuke and press Enter. This will begin the wiping process.
However, pressing simply pressing Enter will give you more options and allow you to choose what level of security you wish to employ in your data wipe.
6. Select the drive that you want to wipe and then type M.
7. Now select from the security options you are given. The DoD options are the standards used by the Department of Defense. The most secure option is the Gutmann Wipe, but this is also the longest method. DBAN recommend the last option, the PRNG Stream wipe as sufficient for most users, but the choice is yours. The spacebar will confirm your selection.
8. Make sure that the drive you want to wipe is still selected, then press F10 to start the erasing process.
9. The time required to complete the task will depend on the size of your disk, the amount of data on it, and the security method you chose. It can take several hours to complete, but you will soon have the peace of mind that ensures nobody will ever be able to recover any of your data from this hard drive again.