How does one sell a computer safely?

[Count Dooku]

Long story short, cash is really short these days. Between the misses and I, we have three computers. We're selling her laptop and her desktop (for a few hundred dollars each, probably) and my question is, what needs to be done to ensure this is done safely? I'm not computer savvy, at all. I'm a biochemist Jim, not a computer engineer! My brother in law suggested a program called Eraser. We've kept both digital and hard copies of every piece of financial information on all three computers for years now, so you can see my concern. Is that program a good one to use?

Also, has anyone had any luck with ebay? I've purchased a film camera and lots of lenses there before, but I've never sold anything. Are there other options? One computer we're selling has an AMD x2 3800+, two gigs of DDR,an Nvidia 7800gt GPU, and a 500 watt PSU. Would I have better luck parting that one out? I know it won't fetch much beyond $200, and that might even be optimistic (250 gig hard drive, though).

My dad sold a computer a few years ago, and not long after, someone bought a boat on one of his credit cards. Luckily, he didn't have to pay for it.

Thanks for any help you can offer. I mostly lurk on the forums and read the articles, but this is a great community

[Mr Bean]

Well formating the drives is a good place to start. I remember in the old days there was a standard option to write zeros to the entire drive IE overwrite all information on the drive with junk. The shop I worked before I joined the service did that back in the Windows 95 days.

The easy way is to simply not sell the hard drive. Sell it as is with the software all the parts but no HD. You might get a little less for it but you sure as heck will get some peace of mind.
If you want to destroy the HD I have plenty of tips for that.

[Count Dooku]

Well formating the drives is a good place to start. I remember in the old days there was a standard option to write zeros to the entire drive IE overwrite all information on the drive with junk. The shop I worked before I joined the service did that back in the Windows 95 days.

The easy way is to simply not sell the hard drive. Sell it as is with the software all the parts but no HD. You might get a little less for it but you sure as heck will get some peace of mind.
If you want to destroy the HD I have plenty of tips for that.

o_O What do you mean write zeros to the entire drive?

I feel like such a noob

[Sir Sirius]

You could try http://www.dban.org/ used it on an old laptop of mine last September and as far as I could tell it did a clean sweep (though I'm no data recovery expert).

[Big Phil]

You can also format the hard drive repeatedly. It won't necessarily erase every last bit of data, but it should deter anyone short of a government organization from trying to recover your data from the hard drive.

That being said, Eraser or Wipedrive are theoretically better, or you can just not sell the hard drive.

[Count Dooku]

You could try http://www.dban.org/ used it on an old laptop of mine last September and as far as I could tell it did a clean sweep (though I'm no data recovery expert).

Ah, excellent. If I wanted to re-install the OS back on to the computer, would that be hard? I have an old copy. I don't want to have a complaint levied against me because it didn't come with an OS, or a hard drive. People tend not to pay attention to what they're buying on Ebay and scream SCAM when they didn't get what they thought they were. I remember when the Xbox 360 first came out someone paid several hundred dollars for a picture of the system

[Mr Bean]

o_O What do you mean write zeros to the entire drive?

I feel like such a noob

Well data is stored as ones and zeros in it's most basic form. If you "zero" the drive it means taking the hard drive and over-writing everything with just zeros. All the ones get zeroed so the hard drive is nothing but zeros. However if a person has some skill in HD repair its still possible somehow to read a zeroed drive if it's only zeroed once.

This is the part where I shrug my shoulders because the "why" I knew, the "how" I do not. Why for example are classified hard drives get a high powered magnet run over them several times and then are "field destroyed" AKA we use a screwdriver or chisel and hammer to break the hard drive open and exposes the disks. Re-run the magnet directly over the disks then break the disks themselves.

[Master of Cards]

Well formating the drives is a good place to start. I remember in the old days there was a standard option to write zeros to the entire drive IE overwrite all information on the drive with junk. The shop I worked before I joined the service did that back in the Windows 95 days.

The easy way is to simply not sell the hard drive. Sell it as is with the software all the parts but no HD. You might get a little less for it but you sure as heck will get some peace of mind.
If you want to destroy the HD I have plenty of tips for that.

o_O What do you mean write zeros to the entire drive?

I feel like such a noob

Data is stored as patterns of zeros and ones, (think very simple DNA if you're a Bio Sci) if you make the whole hard drive 0 you got rid of your data.

Basically any program you use do it twice, or use 2 different products, the more formats (resetting everything to 0) the less likely anything can be recovered off your drive.

and reinstalling wouldn't be an issue, you're just erasing the data not destroying the drive.

[Count Dooku]

You can also format the hard drive repeatedly. It won't necessarily erase every last bit of data, but it should deter anyone short of a government organization from trying to recover your data from the hard drive.

That being said, Eraser or Wipedrive are theoretically better, or you can just not sell the hard drive.

I'm almost leaning toward just hooking up the old hard drives to the computer we're keeping, but we really need the money, and I'm not sure how quickly it would sell without a hard drive. I know I'd be reluctant to buy it.

Well formating the drives is a good place to start. I remember in the old days there was a standard option to write zeros to the entire drive IE overwrite all information on the drive with junk. The shop I worked before I joined the service did that back in the Windows 95 days.

The easy way is to simply not sell the hard drive. Sell it as is with the software all the parts but no HD. You might get a little less for it but you sure as heck will get some peace of mind.
If you want to destroy the HD I have plenty of tips for that.

o_O What do you mean write zeros to the entire drive?

I feel like such a noob

Data is stored as patterns of zeros and ones, (think very simple DNA if you're a Bio Sci) if you make the whole hard drive 0 you got rid of your data.

Basically any program you use do it twice, or use 2 different products, the more formats (resetting everything to 0) the less likely anything can be recovered off your drive.

and reinstalling wouldn't be an issue, you're just erasing the data not destroying the drive.

I do mostly protein structure work, but the sequence must first be known (which is often derived from the coding regions of a gene). The analogy makes sense.

So, if I used dban, the OS would still be on the computer? The site doesn't seem to contain much in the way of instructions...

[Sir Sirius]

Ah, excellent. If I wanted to re-install the OS back on to the computer, would that be hard? I have an old copy. I don't want to have a complaint levied against me because it didn't come with an OS, or a hard drive. People tend not to pay attention to what they're buying on Ebay and scream SCAM when they didn't get what they thought they were. I remember when the Xbox 360 first came out someone paid several hundred dollars for a picture of the system

I had no problems with a fresh XP installation.

So, if I used dban, the OS would still be on the computer? The site doesn't seem to contain much in the way of instructions...

No, dban writes over anything and everything on the drive with random numbers, there will be nothing left on the drive but arbitrary garbage.

[Count Dooku]

Ah, excellent. If I wanted to re-install the OS back on to the computer, would that be hard? I have an old copy. I don't want to have a complaint levied against me because it didn't come with an OS, or a hard drive. People tend not to pay attention to what they're buying on Ebay and scream SCAM when they didn't get what they thought they were. I remember when the Xbox 360 first came out someone paid several hundred dollars for a picture of the system

I had no problems with a fresh XP installation.

So, if I used dban, the OS would still be on the computer? The site doesn't seem to contain much in the way of instructions...

No, dban writes over anything and everything on the drive with random numbers, there will be nothing left on the drive but arbitrary garbage.

So, if I use dban, I WILL have to reinstall xp? That doesn't seem like much of a headache.

Does anyone have a preferred place they sell electronics, aside from eBay? I'm tempted to set the reserve there at $250 and see what happens

[Sir Sirius]

So, if I use dban, I WILL have to reinstall xp? That doesn't seem like much of a headache.

Yeap. Dban will do away with the existing OS and everything else you had on the drive too. So you will need to reinstall all other programs, all drivers and so on as well.

[lukexcom]

Dban should be a good, free tool. Download it, burn a cd from the .iso file included in the .zip file, boot your computer from the CD, and let it do a pass.
Secure Erase is also a good, free tool.


It used to be remotely possible to recover very small chunks data after one overwrite pass on very small hard drives (prior to about 2000) and, more successfully, floppy disks. However, with any modern hard drive that's been properly wiped, the probability of correctly recovering a continuous chunk of a 1 KB of data (the equivalent of this post's text content) is nearly impossible, even if using magnetic force microscopy. Even Peter Guttman, who inadvertently started the "we need 36 passes to banish the data-recovery-evil-spirits!" craze, addressed this in the later-appended epilogues of his 1996 work.

So do one pass with Dban or SecureErase, and sleep well.

There is much misunderstanding out there about data recovery after a hard drive wipe. My company's Security Tiger-Team (they assess each newly acquired facility after a merger/buyout) swore to me that this was not true, that they themselves have "recovered meaningful data" off of drives that were wiped by single-passes of Dban, and claimed that the only way is the "Government-approved six-pass method", but I didn't press the issue.

[Count Dooku]

Dban should be a good, free tool. Download it, burn a cd from the .iso file included in the .zip file, boot your computer from the CD, and let it do a pass.
Secure Erase is also a good, free tool.


It used to be remotely possible to recover very small chunks data after one overwrite pass on very small hard drives (prior to about 2000) and, more successfully, floppy disks. However, with any modern hard drive that's been properly wiped, the probability of correctly recovering a continuous chunk of a 1 KB of data (the equivalent of this post's text content) is nearly impossible, even if using magnetic force microscopy. Even Peter Guttman, who inadvertently started the "we need 36 passes to banish the data-recovery-evil-spirits!" craze, addressed this in the later-appended epilogues of his 1996 work.

So do one pass with Dban or SecureErase, and sleep well.

There is much misunderstanding out there about data recovery after a hard drive wipe. My company's Security Tiger-Team (they assess each newly acquired facility after a merger/buyout) swore to me that this was not true, that they themselves have "recovered meaningful data" off of drives that were wiped by single-passes of Dban, and claimed that the only way is the "Government-approved six-pass method", but I didn't press the issue.

I'm beginning to think that online banking is not the way to go, nor should I store such information on my computer anymore. I would imagine that most identity theft rings operate by stealing information obtained via hard drives, or the like. One thing I haven't done in awhile is a credit check...perhaps that's something I should do ASAP. I'll do the one pass with dban, and reinstall xp. Thanks!

[Darth Nostril]

This is the part where I shrug my shoulders because the "why" I knew, the "how" I do not. Why for example are classified hard drives get a high powered magnet run over them several times and then are "field destroyed" AKA we use a screwdriver or chisel and hammer to break the hard drive open and exposes the disks. Re-run the magnet directly over the disks then break the disks themselves.

Because hard drives are magnetic storage media, overwriting still leaves an echo of the previous data in the physical structure of the disc that the latest in forensic recovery technology can reassemble, so disks that held classified/sensitive material get physically nuked beyond the ability of data forensics to reconstruct.

[Lt. Dan]

Does anyone have a preferred place they sell electronics, aside from eBay? I'm tempted to set the reserve there at $250 and see what happens

Sell local, no shipping cost other than maybe meeting someone in a public place for the exchange.
http://www.craigslist.org
It's pretty good around these parts, anyway. I've sold somethings and didn't have any problems. Make your post and, if you want, post your phone number to get quick sale. The default is that they will scramble you email, so you become anonymous. Your post is listed as it's received. You could and maybe should include photos. I usually don't look at the posts if there is no pic, but that's just me. You can repost daily, but it will sit there until you delete it through the email you get when you start the post. Over all, I love that site and it worked when we had a yard sale and when I moved at the end of June. When I had my number posted for a while, it was ringing all day. Just be careful, there is no middle man, so don't be taken advantage of.

That being said, it may be worth to sell it to someone in your community as a [insert holiday of choice] gift. Good luck.

[lukexcom]

Because hard drives are magnetic storage media, overwriting still leaves an echo of the previous data in the physical structure of the disc that the latest in forensic recovery technology can reassemble, so disks that held classified/sensitive material get physically nuked beyond the ability of data forensics to reconstruct.

This not really relevant to modern, multi-gigabyte drives anymore, from which you essentially cannot recover any kilobytes (hell, good luck getting even 8 consecutive bits!) of meaningful data, no matter what fanciful, multi-million dollar gadgetry you have. If anything, these physical destruction policies are still a good idea in order to prevent human errors (i.e. wipe not done properly).

One wipe will do, or destroy the drive if you don't trust your abilities to do it right.

[General Zod]

Does anyone have a preferred place they sell electronics, aside from eBay? I'm tempted to set the reserve there at $250 and see what happens

There's always your local Craigslist, but how much cash you get out of the machine might be lower than eBay. Just make sure you meet them in person and they pay you in actual cash, as opposed to checks or the like. Unfortunately Craigslist probably has more scammers than eBay, but meeting them in person will cut down 95% of the fakers. I've sold at least one old laptop that way.

[Zixinus]

How can anybody recover from a format C: ? Sure, you can type unformat, but by then, the only way for someone to see what was on the hard drive is to go looking for it. You don't have to tell your client that you stored financial information on the HDD.

[Darth Nostril]

Because hard drives are magnetic storage media, overwriting still leaves an echo of the previous data in the physical structure of the disc that the latest in forensic recovery technology can reassemble, so disks that held classified/sensitive material get physically nuked beyond the ability of data forensics to reconstruct.

This not really relevant to modern, multi-gigabyte drives anymore, from which you essentially cannot recover any kilobytes (hell, good luck getting even 8 consecutive bits!) of meaningful data, no matter what fanciful, multi-million dollar gadgetry you have. If anything, these physical destruction policies are still a good idea in order to prevent human errors (i.e. wipe not done properly).

One wipe will do, or destroy the drive if you don't trust your abilities to do it right.

What have you been smoking? The forensic systems that exist today (admittedly there are only a few publically acknowledged in existence) are capable of recovering data from discs that have been supposedly destroyed with fire.
Wiping the disc is nowhere near sufficient, format C: is woefully inadequate, the physical structure of the HD still retains an echo of the wiped data in the grains of the platters, this is why physical destruction of HDs that hold classified/sensitive data is mandatory.

[Glocksman]

Because hard drives are magnetic storage media, overwriting still leaves an echo of the previous data in the physical structure of the disc that the latest in forensic recovery technology can reassemble, so disks that held classified/sensitive material get physically nuked beyond the ability of data forensics to reconstruct.

This not really relevant to modern, multi-gigabyte drives anymore, from which you essentially cannot recover any kilobytes (hell, good luck getting even 8 consecutive bits!) of meaningful data, no matter what fanciful, multi-million dollar gadgetry you have. If anything, these physical destruction policies are still a good idea in order to prevent human errors (i.e. wipe not done properly).

One wipe will do, or destroy the drive if you don't trust your abilities to do it right.

What have you been smoking? The forensic systems that exist today (admittedly there are only a few publically acknowledged in existence) are capable of recovering data from discs that have been supposedly destroyed with fire.
Wiping the disc is nowhere near sufficient, format C: is woefully inadequate, the physical structure of the HD still retains an echo of the wiped data in the grains of the platters, this is why physical destruction of HDs that hold classified/sensitive data is mandatory.

Possibly.

That said, only a very few select folks will even be worth exerting that kind of effort over.
IOW, unless the OP is some kind of secret agent, scientist, or banker with secrets worth $$$, I doubt that the random buyer of his PC from eBay or craigslist will have either the will or the capability to retrieve any private data from the drive once a reformat and reinstall of windows has been performed.

I've sold a lot of used machines and parts over the years and I've never been bitten in the ass WRT used hard drives and private data after a reinstall of the OS.

Of course, YMMV.

[lukexcom]

What have you been smoking? The forensic systems that exist today (admittedly there are only a few publically acknowledged in existence) are capable of recovering data from discs that have been supposedly destroyed with fire.
Wiping the disc is nowhere near sufficient, format C: is woefully inadequate, the physical structure of the HD still retains an echo of the wiped data in the grains of the platters, this is why physical destruction of HDs that hold classified/sensitive data is mandatory.

Sources? What mystical methodology of the recovery of data after a full drive wipe do they use? How does this methodology make irrelevant the empirical evidence proving the near impossibility of recovering any meaningful data (in the 1KB range) on modern multi-gig drives after single-drive-wipe?

Do you even know how data recovery works?

[Zixinus]

Are we talking about the absolute remote possibility of someone taking out the HDD's disk and using god-knows-what kind of tracking based on the immensely faint magnetic imprints left over on the disk after thousands of rewritings?
How many such machines even EXIST? And why are we worrying about something like this happening to someone who just wants to sell his old computer?

[Beowulf]

If you're paranoid(-ish) DBAN is an excellent piece of software. Then reinstall Windows over, and essentially no-one is going to go digging to the level required.

Now, the government has a different set of requirements for hard drives, but that's because every one of them that I know of having been disposed of went to the NSA. After they went through a damned strong magnet. Fire has a different effect on hard drives than being wiped and having a magnet run over it (the last essentially kills a drive, BTW, assuming you use a powerful enough magnet (which most aren't)).

[Ariphaos]

There is much misunderstanding out there about data recovery after a hard drive wipe. My company's Security Tiger-Team (they assess each newly acquired facility after a merger/buyout) swore to me that this was not true, that they themselves have "recovered meaningful data" off of drives that were wiped by single-passes of Dban, and claimed that the only way is the "Government-approved six-pass method", but I didn't press the issue.

The government-approved method is visually verifiable destruction of the media, at least at the facility I was at.