[hughesa]

Basically, I am selling my PC, so have reinstalled a clean version of windows. Now, I often hear of how people sell their PCs and the new owner sometimes steals their personal information. When I reinstalled the xp it says all data will be erased but just wanted to check. I have XP and I reinstalled using built in Complete Recovery, no cd.

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No this is not a 100% safe way of preventing that no data can be retrieved, it would however prevent the average user from doing it.
The safest option that I am aware of is DBAN http://download.cnet...4-10151762.html the good thing about this program is that it allows you to choose what is wiped out so if you had a HDD with 2 partitions on it 1 for data only and a smaller one purely for the OS you can just wipe out the partition with your data on it, I hope this helps.

[phillpower2]

No this is not a 100% safe way of preventing that no data can be retrieved, it would however prevent the average user from doing it.
The safest option that I am aware of is DBAN http://download.cnet...4-10151762.html the good thing about this program is that it allows you to choose what is wiped out so if you had a HDD with 2 partitions on it 1 for data only and a smaller one purely for the OS you can just wipe out the partition with your data on it, I hope this helps.

[Kemasa]

You should wipe out the whole disk, not just your data partition. Temp. files and such can be stored on the system partition, as well as other information, such as the registry. It is not worth the slight time savings to take the risk. Just run it on the whole disk, then reinstall (if you want or need to).

[phillpower2]

You should wipe out the whole disk, not just your data partition. Temp. files and such can be stored on the system partition, as well as other information, such as the registry. It is not worth the slight time savings to take the risk. Just run it on the whole disk, then reinstall (if you want or need to).

This is of course the safest option, it just means that you will not be able to offer the PC for sale with an OS on it (which your OP suggests is what you would like to do) unless you acquire a legitimate OS disk from somewhere of course.

[Kemasa]

If there is separate partition for the re-install, then that could be left alone.

Another option, which I did years ago, was to write a program which wipes out the free disk space to ensure that data can not be recovered (easily).

There is a conflicting desire, one is to have an OS on the machine and the other is to ensure that no data is available. The install does not actually wipe everything out (overwrite), even though it claims it does. In part that is because it creates a new filesystem, which makes it much harder for the average user to recover the data, but it still can be done.

[Digerati]

When I reinstalled the xp it says all data will be erased but just wanted to check.

Understand that no one is going to be able to accidentally discover your data or personal information. They would have to be actively and intentionally trying to recover previously deleted data using special data recovery tools/software. So while the potential to discover personal data on used hard drives is a very real concern, the typical scenario involves a badguy who seeks out used drives to analyze.

Since you already reinstalled Windows, I am assuming you don't want to wipe the disk and have to reinstall Windows again. If you have no idea where that hard drive will end up, then I would wipe the drive and start over - or drill three holes through the drive around the spindle and sell the computer without a drive, or OS.

There are a couple alternatives that I think will provide 99% certainty any personal information will be unrecoverable. The first is to copy a bunch of music files or photos to the drive and fill up the drive. Then delete all those files and fill up the drive again, then delete them once more. That will overwrite virtually every available space on the drive - which is what a wipe program does - only it does it many times, and with random data, or special patterns of data.

Option two is to use http://www.ccleaner....wnloading-slim' class='bbc_url' title='External link' rel='nofollow external'>CCleaner. It has an option called "Drive Wiper" that will "wipe" (write a bunch of random 1s and 0s) to the free disk space.

Finally, as soon as, and every time that computer is used by the new owner, new files will be stored on the drive. And each time new data is written to a cluster on the disk, any residual magnetism resembling your data in that cluster is driven further and further into oblivion. So, if you know where this computer will end up, and you feel comfortable they will be not intentionally perform "forensic analysis" on your disk as soon as they get it, then I would not be too concerned.

[Kemasa]

Digerati said it very well. I tend to be more paranoid (just because you are paranoid doesn't mean that someone isn't after you), so I would do something different, just to be safe, but as was said the risk is low.

Using the suggestions that Digerati said would be good enough (fill the disk/wipe the free space).

[Digerati]

I tend to be more paranoid

Well, I did say I would wipe the drive to be sure if I did not know where the drive would end up. And to be sure, the two methods I described above are good enough to prevent all but the most qualified forensic analyst using very sophisticated and expensive equipment, from getting your data. And even then it would take that analyst a long time to retrieve anything, and enough to be usable. No badguy is going to waste his time where there are so many easy pickings around. They would have to be targeting you specifically, and have deep pockets too.

The equipment and training is why if you accidentally delete files and an unerase program does not help, it can cost many $100s or even $1000s to pay a data recovery service - and even then, there's no guarantees.

[Kemasa]

Yes, but I would wipe the disk even if I know exactly where it is going, even if it is a family member :-).

Using the free space wipe is really good enough after an OS reload since there should be no temp. files around or any other files which have personal information.

[Digerati]

Yes, but I would wipe the disk even if I know exactly where it is going, even if it is a family member :-).

Especially family members!

Wiping is always the best option.

[hughesa]

Thanks for the help but I am a little confused. For a start, I do not wish to sell without the hard drive or an operating system as this will obviously lower its value, and it is not worth that much as it is and I am hoping to get as much as I can for it. I will be selling it to Cash Converters so I do not know whose hands it will end up in. Am I right in saying that when I reinstalled the operating system, it did not overwrite the previous operating system but actually created it on a separate part of the hard drive (i.e. a partition)? Therefore, all the files and folders are still there on the hard drive?

[hughesa]

Does it not make a difference that I used the built in Windows Recovery as opposed to using a CD? Will it still have created a new partition?

[Digerati]

Am I right in saying that when I reinstalled the operating system, it did not overwrite the previous operating system but actually created it on a separate part of the hard drive (i.e. a partition)? Therefore, all the files and folders are still there on the hard drive?

If you performed a clean install, and replied to continue when it warned you that all data will be lost, then the previous operating system was overwritten. If it was created on another partition, you would see the other partition as a separate drive under My Computer, AND you would be prompted which OS you wanted to boot to when you powered up.

But overwriting a program does not mean each and every storage location on the disk used by the old program is overwritten by the new. The extra are abandoned and simply "marked" as available storage space in the file tables. The data is still there, but it takes special disk analysis software to find and recover it. But even then, it would be like a 1,000,000 piece jigsaw puzzle with 1/2 the pieces missing, and the rest picture side down.

Again, the best solution is to wipe the drive and start over. But I think if you run Drive Wiper a couple times, you will be fine. For an extra warm fuzzy, fill up the disk a couple times with large music or video files. Remember, delete, format or erase (really the same as delete) don't delete or erase anything. The space is marked as available and the 1s and 0s in there are just abandoned. A wipe program does not erase, it just changes the 1s and 0s into a different set of 1s and 0s.

You might also download and install Recuva, from the makers of CCleaner, or Restoration to see if you can find any of your old data.

[hughesa]

So, should I run DBAN, and then reinstall the OS again (because DBAN will also remove the OS I presume?)? And you think that should do the trick?

[Kemasa]

That is the most secure way to do it, BUT that assumes that you have the CD to reload the OS. If you don't have the CD, then you will be left with a machine that has no OS.

The second best solution, which should be good enough (unless you are a spy :-), is to wipe the free disk space after reloading the OS using the complete recovery.