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Normally PCs come with set up discs which will restore the machine to a factory condition. If you have one of those, use it.
If you don't want someone else spying what was on your PC, then the easiest way to completely guarantee no data is left on your HDD is to take it out and replace it with a new one!
Failing that, there's some utilities that will wipe each sector on your hard drive with random information multiple times to remove whats on there.
That utility, along with some great others for this type of thing are included on a free download of Ultimate Boot CD [ultimatebootcd.com...]
Make sure you get ALL of your information that you need off before running one of these utilities ;)
Once you replace the hard disk you'll have to install Windows + drivers etc manually. You may have a "recovery CD" which may work for this job.
It all depends on your level of paranoia. :)
Given the price of (desktop) hard drives, this isn't that expensive a security measure. (How much is it worth to you, to keep that old data away from prying eyes?) But since we're discussing a laptop - which I highly suspect has a proprietary hard drive design (read: more expensive to replace) - one would seriously need to consider the cost-to-benefit ratio of my methods.
But it does work better than any software solution...
I'd like to share a story with you all on an experiment I did, since I have a keen interest in this particular field (forensics, etc). A few months back I handed my brother a hard drive to use that I had 'dd if=/dev/zero of=/dev/da0' (for non-unix people, that means rewrite each bit on the drive with a '0'). I told him to use it has though it was a regular hard drive. I got him to install XP on it and surf on it whenever he thought of it, and to set up his email on it and so on... Basically to get some mileage out of it and fill it up.
About 3 weeks later I came back and asked him for the drive back. I told him to format the hard drive (not using any scrubbing tools), and told him that there was an email that I'd sent to him a couple of weeks earlier that contained a bunch of pictures, and he said he remembered it. I asked him if he'd surfed with it at all, to which he said yes. He even typed up a couple of emails and saved them under drafts, had used photoshop to edit some pictures, etc etc. Normal Usage.
Almost everything that he had done on that box, I could see. Things he had deleted (and actually thought he had deleted), were still there on the drive, marked as "clear" by the filesystem, but not overwritten yet, and so on. I was able to find the images from the emails and so on.
A fun little experiment, and it helped him see how vulnerable you really are. I haven't tried it with any scrubbing, so I can't attest to one product's benefits versus another.
If you're just looking to protect yourself from the average user, a simple single-pass "dd" will do, but if you're worried about law enforcement or other 3-letter agencies, then first wiping data with zero bit data, multiple times (IIRC, 8x is the DOD minimum), then with random data ( BTW: random doesn't really help you in the sense of covering up the data, it slows everything down, but it MAY make whoever is looking at the data think that the drive is encrypted, and spend more time following a useless path of investigation). Then destroying the drive a la Balam would be good. Keep in mind that you don't really know what the person you're selling it to is going to do with it.
The only other best thing is to find a smelt where you can burn the thing. But that's just a LITTLE extreme. ;)
"YOU CAN´T "REAL" DELETE DATA ON HARDDISKS OR FORMATE HDD´S"! YOU MUST DESTROY THE DISK!
cu and have fun :)
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[edited by: tedster at 7:03 pm (utc) on July 3, 2005]
Also, if you search for "eraser", a totally free one should come up. Slow, but works great.
question, simply reformatting your computer (not the quick reformat) doesnt erase all your information? I thought that completely destroys all the data on your hard drive. Can the goverment and people who really want to see your data find that deleted info after a reformat?
I am sure a high tech forensics lab with skilled employees being paid $120,000/year salaries could, within a few hours on equipment costing tens of thousands of dollars could recover all your old data. Then of course they would have to spend a few hours sorting through the old data. The cost to taxpayers is only five or six thousand dollars per hard drive. Sad thing is, they do this everytime someone sells an old computer.
We modified our format code to made multiple passes writing patterns designed to obliterate data instead of single passes which pretty much zapped everything.
If you want to make sure it's GONE GONE, use a data killer program mentioned above and the restore disk AND run defrag just to make sure nothing points where it did before.
However, nothing works better than a bulk eraser and a sledgehammer :)
I am sure a high tech forensics lab with skilled employees being paid $120,000/year salaries could, within a few hours on equipment costing tens of thousands of dollars could recover all your old data.
Or some sysadmin, or anyone else that's slightly knowledgeable, or would like to learn and experiment, and has a few hours of time, using their old P-400 and a large hard drive to store images of "formatted and cleaned" hard drives. It's not hard to use either freely available or commercial products to tear apart what was once on a formatted hard drive. I have with ease restored partitions from an fdisk, and read hard drives that were formatted with windows' format or any other "format". And we all know deleted files are not deleted immediately. This is all using free/Opensource software, time and a little knowledge.
Then of course they would have to spend a few hours sorting through the old data. The cost to taxpayers is only five or six thousand dollars per hard drive.
Taxpayers? Why do you think it's only the government that's interested in your data? Have any competitors that would like to look at your code/accounting spreadsheets/policies/passwords/recipes? I would be more paranoid about that than a government coming after me. There are lots more interesting people out in the world than poor little me.
If that doesn't work then a few minutes in liquid nitrogen and a hammer should do it.
You may not sell your laptop to a teenager with coke-bottled glasses living in his parents' basement, but you would probably sell it to me, someone wearing every day business attire, and not really think anything of it. Just because I *look* trustworthy and sound like a nice guy who wants to buy a used laptop to fix up for his aged grandmother, doesn't mean I'm not out to get you. ;)
I know a couple of people that have purchased dozens hard drives at auctions from defunct companies, or 3-year-cycle throw-aways that contained some very interesting data. Nothing too serious, but interesting to see internal emails from companies, even if we've never even heard of them before. We have all entertained the idea of buying lots of used hard drives from auctions and so on, and scouring them for any useful information. Then once that is done, what could we do with that data?
1) Apply for a job at that company as a security consultant,
2) Blackmail them, depending on how juicy the data is,
3) Blackmail an individual in the company (see above),
4) Sell that information to a competitor,
5) Sell that information to a significant other
All very brutal propositions, and nothing that I'm actually interested in, but I'm sure there are people out there that would pay a few hundred bucks for a bunch of 10 GB hard drives, and hope to make some money at it.
Anyway, I'm sort of expanding a little too much on what the possibilities are, but if I've thought of it, I'm sure someone else has, and is actually doing it right now. ;)
A company under investigation, or something, shredded some documents but the police or forensics or whoever deals with such things, searched the memory on the printers and found the documents.
So, maybe a little paranoia isn't such a bad thing.
I plugged in the old machine, then crossed my fingers and tried to read the drive (with the disks spinning in open air) and was able to copy every file I needed off of the drive with no problems.
If you are going to try to destroy a drive, be sure to finish it off. Pulling the lid off didn't destroy it like I was told it would do. In fact it might even make a cool fish tank decoration...
Encase is a piece of forensic software that is widely used by police forces. Test your drive with this and if you cant retrieve anything you're probably safe
However, nothing works better than a bulk eraser and a sledgehammer :)
I am laughing so much it's hard to type. This thread reminds me of how we use to joke years ago about how to get rid of data on a hard drive. This has brought back all those happy memories.
The best advice I remember getting back then was to hit the hard drive at least 100 time with a sledgehammer, then what's left of it throw in front of a moving freight train, then take what's left and meltdown with a cutting torch, then that the raw metal and drop it in the deepest part of the ocean. If you do all that you can sleep well at night knowing that your deleted information is safe.
I'm sorry, this data removal talk is very funny to me. I look forward to reading this thread until it finally plays out!
-F 200 L1000 0
#*$!x:0100 MOV AX,301
xxxx:0103 MOV BX,200
xxxx:0106 MOV CX,1
xxxx:0109 MOV DX,80
NOTE: Type 80 for the primary hard drive - HD 0, or type 81 for the secondary hard drive - HD 1.
In most cases, the primary hard drive is required 80.
xxxx:010C INT 13
xxxx:010E INT 20
xxxx:0110 (Leave this line blank. Press the <Enter> key to continue.)
The message Program terminated normally appears.
Follow this link also
you can't destroy data on your drive with any software. Any software at all. Not a single piece of software at all. Nope. It really doesn't matter if you pay £20,000 for the software, nor if you write over your data 94 times; if someone really wants it then they can get it. Destroying the disk completely is the only sure way.
See, the tracking of the drive head around the platters moves very slightly over time, so all your old data gets left behind on very thin tracks that are left.
Of course, recovery techniques that utilise this are expensive and time consuming, and they're not likely to be used in most circumstances. As has been written many times above, it all depends on your level of paranoia.