Do deleted files remain on my PC?

Should you sell your second-hand computer or is it a risk to your security?

Do deleted files remain on my PC?

YOURLifeChoices member Aaron has purchased a new computer and wants to know if his old computer, used for creating and storing business records, is safe to sell.

Q. Drew,

I have recently purchased a new desktop computer and am unsure of what to do with my old one. It is only a few years old and I’m sure I can get a couple of hundred dollars for it, but it was previously used to create and store sensitive business records. I have heard that even if you delete a file, it still remains in some form on your computer. Is this true and if so, how do I make sure the files are deleted?

A. Hi Aaron,

Congratulations on your new purchase. You are correct in being concerned about the sensitive information which you once stored on your computer. In short, deleted files do remain in some form on your computer after deletion. The best explanation I have found for how the process works is that when you delete a file or program, you are actually deleting the pointer (shortcut) to that location on the hard drive, not the actual file. Once a file is deleted, the space on the hard drive is signalled as available to store new files, but is only overridden once the hard drive needs that space.

You have a few options going forward. The most popular and sensible option is to remove the hard drive from the computer and to sell it without a hard drive. This may make the computer a little harder to sell, but you know your information is protected.

There are also a number of programs which claim to erase this data for you, but there have been many noted cases where up to 35 full wipes of a hard drive have been performed, yet information has still been obtainable.

Finally, if you just happen to have a super magnet sitting around, one of these can be used to wipe the memory off the hard drive.

I have included a video below from a quirky gentleman who explains the process for you in a very fun and interactive format.


    To make a comment, please register or login
    12th Sep 2013
    i have used strong magnets to wipe my hard drive when my pc died. i also formatted the drive before hand.
    12th Sep 2013
    Deleted files only have the first letter, sometimes more, deleted and remain on the drive.
    The best way is to do a "DSD" delete or wipe. This is a Defence Signals Directorate wipe.
    DSD are the "Secret Squirrels" of our intelligence community.
    failing that you may be able to do a complete re-format of the Hard Drive and that should delete all the files.
    If you need assistance post a reply or send an email direct to me via my profile
    Young Simmo
    12th Sep 2013
    I reckon if your computer has something like 2 GB Ram or better and might be worth a couple of dollars. The best way is remove the Hard Drive and buy another one on E-bay for something like $30 to $100. That way you win, and so does your customer. I am not a computer wizard, so if I am wrong feel free to tell me.

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