There are two major reasons to erase the contents of your computer's memory — you are getting rid of the computer (either because it is broken or because you are handing it down to someone) or a software issue requires the complete reformatting of your hard drive. Either way, the data on your computer is more detailed than you may think. Even the most advanced computer user does not find every little detail stored on the hard drive, from previously visited websites to photos or music files or even files from your word processing or financial management programs.
Protecting your data, privacy and anything you do with your computer that could be embarrassing should be the first thing in your mind when deciding what to do with the computer you are getting rid of.
There are two relatively easy ways to erase the contents of your hard drive.
If the computer does not work
If your computer is not functioning and all you plan to do is recycle it or give it to someone to scrap for parts, you need to physically erase the hard drive. To do this, first get a copy of your computer's owner manual. If you do not have it from its purchase, it can be downloaded from the support section of your computer maker's website or from a manual library like retrevo.com.
Using the manual, find the section on how to replace your hard drive. This will show you how to get access to your PCs physical hard drive.
There are two ways to deal with the data at this point. Take a strong magnet (something at least a 1/8-inch thick; paper thin magnets will not work) and rub it on the hard drive's casing. A magnet will damage the files and software stored on the hard drive and render it useless.
The second involves physical destruction of the drive. Place the drive on some newspapers. Take a sledgehammer or rubber mallet and break the casing. This is as permanent as a hard drive erasure as you will get.
If the computer works or if you do not feel like taking the computer apart
You will need to find the disks that shipped with your computer. This is either the actual Windows CD or a Resource CD which was provided by the manufacturer. (If you do not have these CDs jump to the next section.)
Insert the Windows or Resource CD that came with your computer into the CD drive.
Start the computer.
When the computer is started, go to your CD drive and click the Setup icon. This will take you through the process of reinstalling Windows on this computer. Note that you may need the Windows Product Key to prove that you own that copy of Windows.
Click the appropriate next and okay buttons to begin the installation.
If you do not have the Windows CD
Pay attention to the screens that come up during the restart. One of the messages will say something to the effect of "Press XX for Setup." The message's verbiage and key will vary from manufacturer to manufacturer. You will want to press that key.
This takes you to the System Startup Screen, which is the behind the scenes control of your Windows machine. In this screen you will see a choice called "Return the drive to its factory condition."
Move your cursor to this choice and select it. Hit okay at the necessary questions and begin the restoration.
Things You'll Need
Mandatory: Your PC
Optional: A screwdriver, hammer or mallet, Windows or Resource CD that shipped with your computer
Make sure that you have backed up any necessary files from your computer prior to doing any of this.