Wiping HD before selling PC

cormie

Hi,
I was watching a show where all the computers that are recycled end up in Africa and are sold there for dirt cheap. The reporter bought 3 hard drives and from that, was able to see bank details, family plans and everything about 3 folks from the UK, went to their houses and told them their bank details to scare them etc etc..

Anyway, I might be selling about 3 old computers and would like to clear all data but still have a working operating system. Is there any way to do this without having to reinstall the operating system? I just don't want any tech buyers to go snooping in deleted files etc, so is there something that will overwrite the deleted data and do all that too? The pc's I'm selling aren't worth much so don't want to spend too much time on them.

Also, I remember I had a HD that stopped working, I couldn't hook it up to format it and I wanted to dispose of it so before I did, I just hammered it to bits just incase:D Any better way to securely dispose of such a hd?

petes

Check the sticky on essential free software. Check security. A few in there like dban.

aidan_walsh

SysInternals SDelete should do what you want. The more passes, the more secure. Just be warned that it could take quite some time.

Khannie

dban. There was a thread on this a few weeks ago bud.

aidan_walsh

petes wrote:

Check the sticky on essential free software. Check security. A few in there like dban.

DBan will only wipe the entire disk. It won't let you run from inside Windows and only wipe the "free space".

garthv

Id also suggest dban : http://dban.sourceforge.net/

Sets all the sectors on the hard drive to 0 so there is no way of data recovery

Alun

Eraser from http://www.heidi.ie/eraser/default.php will do the job, i.e. erase unused space after you've deleted files normally. You can also create a boot floppy that will do a complete wipe if required.

Pablo

The trick is that these wipe over the sectors over and over again. That way the date can't be recovered. Data is normally deleted on a HD by changing the valid bit to zero, and allowing that sector be be written.
The recovery SW put the sectors back together and ignores the valid bit.

AFAIK anyway.

cormie

Thanks for the replies everyone. Dban will definitely not do it without having to wipe the whole HD? How does Dban do it anyway? Does it do it from dos or do you need to connect the HD you want to wipe to another computer with Dban installed through an external HD connection and wipe it that way?

Does anyone know which, between sysinternals and heidi are better?

aidan_walsh

DBan is available as either a floppy boot image, or a LiveCD.

Anti

If i were you i would sell the pcs without the hdds. Every hdd i have had for the last 6 years or so i still have. Any ones i have had to get rid of i have smashed to bits, so nothing is recoverable.

But if you really wanna sell with the hdds then use dban to wipe, and just reinstall windows.

Baraboo

You can use a programe such as Eraser http://www.heidi.ie/eraser/ to securely wipe selected files on your computer and leave the OS intact. But this would leave the deleted files on your machine subject to being recovered by recovery programes, and this could include far more files than you would imagine. Safest is to use the nuke function from this or any other secure/wipe programe to wipe to US Dept. of Defence standards and then reinstall if you want to resell the PC.

Baraboo

Alun

Baraboo wrote:

You can use a programe such as Eraser http://www.heidi.ie/eraser/ to securely wipe selected files on your computer and leave the OS intact. But this would leave the deleted files on your machine subject to being recovered by recovery programes, and this could include far more files than you would imagine. Safest is to use the nuke function from this or any other secure/wipe programe to wipe to US Dept. of Defence standards and then reinstall if you want to resell the PC.

Baraboo

You can also use Eraser to wipe all unused space, including cluster tips.

cormie

Thanks, I might give eraser a go so.

Is there any way to tell exactly what files are needed by the OS? Would be handy if that was an option in the program, but if it's not, is there a list anywhere that says what you need to keep so I can keep them and nuke the rest?

petes

cormie wrote:

Thanks, I might give eraser a go so.

Is there any way to tell exactly what files are needed by the OS? Would be handy if that was an option in the program, but if it's not, is there a list anywhere that says what you need to keep so I can keep them and nuke the rest?

I'd wipe the whole lot and reinstall the os. Is that an option?

Alun

petes wrote:

I'd wipe the whole lot and reinstall the os. Is that an option?

I agree.

Whilst it may sound easy to just delete all 'personal' data and just leave the OS, that isn't quite as easy as it sounds. Windows has a nasty habit of spreading personal data all over the shop in all kinds of strange places, often sharing folders that hold other non-personal, but often system-critical information. That's not to mention personal files that users have 'accidentally' saved in C:\WINDOWS, 2 or 3 alternative TEMP directory locations, software that puts data in the Program Files folder, the registry etc. etc.

Back in the days of DOS or Windows 3.1, you could pretty much identify every file on the machine and know exactly what it did, and whether it was safe to delete it or not. On a modern XP machine with the obligatory bucketload of soiftware installed that isn't really an option any more IMO.

cormie

I might just do that alright. Thanks for the help everyone:)

Capt'n Midnight

aidan_walsh wrote:

DBan will only wipe the entire disk. It won't let you run from inside Windows and only wipe the "free space".

doesn't spybot claim to remove over 30,000 recently used entries

and as you know there are all the common data mines of temp files / cases of unencrypted passwords in the pagefile and personal data scattered all over the registry

still sdelete is the biz to remove individual files, but to be sure you'd have to delete all backup copies, temp files and set pagefile to 0, sdelete -z , then defrag and sdelete again and then you'd still be at risk of someone finding earlier levels of magnetism under the files that didn't move

dban FTW
or if you are paranoid keep the drive and destroy it yourself using your favorite impliments of destruction