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Many of us get tired of our old computers from time to time and decide to sell them so that we can buy a new model. When we do this, we usually delete our personal files from the computer. It’s quite normal to want to make extra sure that there is absolutely no data remaining on the computer that the new owner might be able to get access to. Before I teach you how to wipe a computer clean, you need to understand something about the way data is stored on a hard drive.

When you do things like visit a website, use computer programs, or save files, data is stored on the hard drive of your computer. Some of you may think that deleting a file or deleting the history from your web browser actually removes this information from your computer but that’s not the case at all.

The only thing deleting this information does is remove a tiny bit of code that names the data and reserves its place on the hard drive. This is what enables you to find the data that you save when you need access to it. It also prevents your computer from storing new data over existing data.

When you delete a file, the file isn’t actually deleted at all. As a matter of fact, it will remain on your computer until new data has been saved over it. Not even formatting your hard drive will remove all traces of this old data!

How To Wipe A Hard Drive Completely

If deleting the file doesn’t actually delete it and reformatting a hard drive doesn’t actually clean it, you might be wondering how do I wipe my hard drive then?

Before I go any further, you should back up anything that you don’t want to lose! You should also make sure that you have a copy of any software, including the operating system, that you plan on reinstalling on the hard drive after you wipe it clean.

How To Wipe A Computer Clean If You Don’t Want To Have To Reinstall Software

If you aren’t concerned with making sure that your drive has been completely wiped, you can use a free program called CCleaner. I’ve written about it before in an article called How To Clean My Computer To Make It Run Faster.

The features that we’re most interested in for our purposes today are the “Cleaner” and “Drive Wiper” features. Before I tell you how to use these features, there’s a couple of important settings that you should know about. The first setting is found in the advanced section of the “Options” menu. You want to make sure that there is NOT a check mark next to the “Only delete files in the Windows temp file older than 24 hours” section.

how to erase hard drive

The other setting is found by clicking on “Options” and then “Settings”. This is where you can tell CCleaner how thorough of a job to do when it is cleaning your system from things like temporary files and web browsing history. The maximum level for this software is the “Very Complex 35 passes” setting. This is the most secure file shredding option that CCleaner has but using it comes with a price and that price is that it will take much longer for the software to work it’s magic.

Now that you have that taken care of, it’s time to clean your system. All you have to do is click on the “Analyze Button”. When you do this, CCleaner is going to scan your system for any files that it can clean up for you. Then it will report its findings and tell you some information about the files that will be deleted if you choose to continue. You’ll see a screen like the one below.

CCleaner Analysis Complete

All you have to do now is click the “Run Cleaner” button and wait while this program does its thing.

How To Wipe Your Computer Clean With The Drive Wiper Feature

If you click on the “Tools” option, you’ll see a utility called the “Drive Wiper”. BE VERY CAREFUL WITH THIS UTILITY! This utility gives you the option of wiping the entire hard drive or just any free space that it finds. Keep in mind that recently deleted files will be considered free space. I actually use this utility quite frequently with my personal laptop but I tend to be a bit paranoid about these kinds of things.

CCleaner Drive Wiper Screenshot

In a nutshell, what this feature does is look for any free space of the drive and then when it finds it, new data is saved over the old data. Depending upon which setting you selected, CCleaner might save new data over the old data as many as 35 times.

How I Wipe Files From A Computer That I’m Selling

If I was going to sell my old computer I would personally follow these steps.

  1. I back up any files that I want to save. These usually include files like personal photographs, personal documents, etc.
  2. I delete the files that I don’t want the new owner to have access to.
  3. I run CCleaner with the 35 pass setting to clean both the history and deleted files from the computer.
  4. I run the Drive Wiper feature at the 35 pass setting to wipe the free space on the drive.
  5. I use the restore software that came with the computer to return the computer to the condition it was in when I bought it.
  6. I reinstall CCleaner and run the drive wiper feature on the free space one more time just as a precautionary measure.

Disclaimer: I’m not a data recovery expert so I can’t guarantee that the steps I’ve outlined in this article will make it impossible for a data recovery expert to use some kind of software to mine data from a hard drive that has been wiped using the methods described in this article. These methods are the methods that I’m personally comfortable with using on my own computers. You’re responsible for the data on your computer and what methods you use to secure this data or wipe your drives is up to you and you alone bear the full responsibility for securely deleting data from your computer’s hard drive.


I receive compensation due to affiliate links or endorsements on this website: Disclosure of Compensation