Wiping a computer before you sell

Lindylou54

We have two computers at home due to my husband bringing his home when he closed his business. We need to get rid of one, but am worried about how you go about wiping it clean of all the information on it.

Any suggestions?

sf

not the only such program, but it's free...

http://www.killdisk.com/features.htm

it just zeros out the data, so in theory someone with a lot of time and effort could still recover info, which explains why there's also a paid version that will repeatedly overwrite the data to make it totally unrecoverable.

maybe someone else will know of a freeware one that repeatedly overwrites, but be prepared to leave it for many many hours working away if you want it at its most securely erased.

Reluctant_spender

The only safe way is to destry the hard drive. Is it worth installing a new chaep drive?

nickmack

Reluctant_spender wrote:

The only safe way is to destry the hard drive. Is it worth installing a new chaep drive?

Even trashing the drive doesn't work in all cases!!

As the OP hasn't specified to the contrary, I don't think they have any military secrets on the drive. Therefore, overwriting a few times, using a program like the one suggested by sf should be more than sufficient.

nemo183

This is a subject close to my heart, having been requested to do it for several customers.

It is very easy to just reformat the HD, which costs nothing, and appears to wipe the drive.

However, as others have said, it would be the work of seconds, if you wanted, to undo this.

I have a reasonable degree of faith in "East-Tec Eraser", which will wipe drives to a number of degrees of security, including the highest level that us ordinary people can buy.

Depending on your level of concern, when you wipe a drive, what you really have to do is use a program that physically overwrites each "blank" sector of the disk with new info, ensuring that whatever was there, is gone.

However, whilst this will satisfy 99% of most peoples requirements, from a strictly forensic point of view, it may still be possible to retrieve the overwritten data in a number of ways. Since doing this would cost a very large amount of money, it's unlikley ever to happen to the average person unless they have been doing some very, very bad things.

These people will just remove the hard drive - a few seconds of work - and crush it with a hammer, and then chuck whatever remains over several differnent bridges. On the whole, this is 100% effective.

In the most unlikley event these people have a social conscience, they will then replace the HD with a cheap OEM replacement.

Finally, it's worth mentioning that there is a conspiracy theory that says that that the companies that sell the most effective erasurer software, may also have the possibility of a major revenue stream by leaving a "back-door" (or even be owned/funded by) those that would most like to retrieve the info.

I would stress that there has never been a case proven of the above, but equally rumours still circulate.

It would be most interesting to hear other peoples expert views on this......

albertross_2

For a general cleanup, delete all you personal files, then run these
one after the other (tick all the boxes).

http://www.ccleaner.com/
http://www.theabsolute.net/sware/clndisk.html

To completely wipe you hard disk, and make all data unrecoverable:


http://www.cbltech.ca/data-shredder.html
http://dban.sourceforge.net/
both free. Overwrite 7 or more times.

nemo183

albertross wrote:

For a general cleanup, delete all you personal files, then run these
one after the other (tick all the boxes).
http://www.ccleaner.com/
http://www.theabsolute.net/sware/clndisk.html
To completely wipe you hard disk, and make all data unrecoverable:
http://www.cbltech.ca/data-shredder.html
http://dban.sourceforge.net/
both free. Overwrite 7 or more times.

This is top class advice, for the kind of removal that most people need. However, I cannot stress enough that even this comprehensive "overwrite" technique does not represent a 100% forensic solution. Without going into details, it's not just the byte of data on the HD track you need to eliminate, it's also the trace/ghost evidence that overspills the track on either side that represents the "smoking gun".

Aiadi

nemo183 wrote:

This is top class advice, for the kind of removal that most people need. However, I cannot stress enough that even this comprehensive "overwrite" technique does not represent a 100% forensic solution. Without going into details, it's not just the byte of data on the HD track you need to eliminate, it's also the trace/ghost evidence that overspills the track on either side that represents the "smoking gun".

Gosh, you must spend a lot of time watching spooky movies....:rotfl:

MoneySavingGenius_2

If you have a working floppy or cd-rom (need to be set in your bios to boot before your hd) drive download the Maxblast 4 utility, reboot your PC with it in the drive and select the zero format option.. This writes zeros to every sector on the drive. It works with any manufacturers hard drive.

http://www.maxtor.com/portal/site/Maxtor/menuitem.8db0c3d6932ced37294198b091346068/?channelpath=%2Fen_us%2FSupport%2FSoftware+Downloads%2FView+By+Category%2FDesktop+Storage%2FDiamondMax+Family

Then just reinstall your operating system.

nemo183

Aiadi wrote:

Gosh, you must spend a lot of time watching spooky movies....:rotfl:

If only.......

Complete, absolute deletion of an HD file can only be done with a hammer and a considerable depth of water. Anyone that tells you differently is wrong.

The very practical posts made so far are good for 99.99% of all users. I repeat, if you have done something very, very wrong (and we're not even approaching the area of anything !!!!!! related), you'd be amazed what can be recovered if enough money is spent.

Just spend a small amount of time understanding how data is actually stored on a HD, and how it "leaks". It's basic physics, and all out there on the net.

If you really want hard facts, then just view the expert evidence from a serious trial on how data was reclaimed.

Since I doubt that even with the massive numbers that MSE now reaches, for obvious reasons it is a tad light on money launderers and organised crime, it is a fact that whilst it is seldom reported, the "authorities" have at their disposal tools that are designed to match commercially available progs that are aimed in the opposite direction.

Their problem is that it is a massively expensive business, so only ever rolled out when a massive amount of money is involved. And just a personal view, I doubt that it's even ever needed in the "war against terror".

So, whilst I can see why you might consider my opinion paranoid, and I agree that most of the posted solutions will do the trick in most cases, it's most unwise to ignore the actual physics of the HD, and just rely on the theory.

MoneySavingGenius_2

As a side note:
the format commands most commonly used (fdisk, etc) don't actually delete anything - in fact all they do is overwrite the master boot record and partition table, then all they do is verify that each byte can be read a few times, so that any bad sectors can be ignored in the new mbr - hence why it takes so long.
I've seen a demonstration of the tool police use to recover data from hard drives - it literally takes 2 minutes to have all the data back when this method of formating is used.
It is out the reach of most people, organisations to recover fully overwriten drives - but it is possible in lab conditions - I guess you have to ask yourself are you that important?