# How do I completely delete everything from my computer in one fell swoop? **URL:** \ **Category:** Factual Questions\ **Created:** [April 22, 2006, 3:22pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749 "2006-04-22T15:22:03Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![chappachula](https://avatars.discourse-cdn.com/v4/letter/c/d2c977/32.png) [@chappachula](https://boards.straightdope.com/u/chappachula)\ **Post date:** [April 22, 2006, 5:04pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/21 "2006-04-22T17:04:16Z")
Can one of you techies please explain to me what the simple format command does? I gave an old computer away to a charity, and simply typed "format c: " to clean it all out. I didn’t have anything to hide , so I’m not concerned for myself.But I stuck a post-it note for the recipient that they would need to re-install Windows because the computer was now “totally empty inside”. (that’s how much tech lingo I know) Now, I know that “delete” doesnt remove a file, it just erases the file name from the master list in the FAT. But I thought “Format” erases everything. Was I wrong? Was the computer not really empty? ---
**Author:** ![Myglaren](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@Myglaren](https://boards.straightdope.com/u/Myglaren)\ **Post date:** [April 22, 2006, 5:14pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/22 "2006-04-22T17:14:42Z")
Reformatting can leave recoverable traces for anyone sufficiently interested and skilled to want to bother but is effective enough for most purposes. Fdisc-ing is better and removing partitions and repartitioning an improvement on that. Reinstalling the OS and office software will go a stage further in overwriting any remaining data. Given the right tools it is possible to recover data that in theory has been wiped. ---
**Author:** ![chrisk](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@chrisk](https://boards.straightdope.com/u/chrisk)\ **Post date:** [April 22, 2006, 6:27pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/23 "2006-04-22T18:27:15Z")
[QUOTE=chappachula] Can one of you techies please explain to me what the simple format command does? I gave an old computer away to a charity, and simply typed "format c: " to clean it all out. I didn’t have anything to hide , so I’m not concerned for myself.But I stuck a post-it note for the recipient that they would need to re-install Windows because the computer was now “totally empty inside”. (that’s how much tech lingo I know) Now, I know that “delete” doesnt remove a file, it just erases the file name from the master list in the FAT. But I thought “Format” erases everything. Was I wrong? Was the computer not really empty? [/QUOTE] No, format regenerates the sector headers IIRC, and clears out the FAT and the root directory… it’s like a ‘delete all’ for a disk. It doesn’t really erase any more than delete does. ---
**Author:** ![cbarnes](https://avatars.discourse-cdn.com/v4/letter/c/a88e4f/32.png) [@cbarnes](https://boards.straightdope.com/u/cbarnes)\ **Post date:** [April 22, 2006, 6:39pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/24 "2006-04-22T18:39:04Z")
How badly do you not want somebody to find that data? Not even degaussing the drive will truly make the data unrecoverable. If you _really_ don’t want the data found, you should toss the drive into a woodchipper because destroying the drive is your only guarantee of unrecoverable data. On the other hand, if it is just some slightly objectionable material just put the bootable restore disk in and follow the instructions. Without considerable effort, the 15 year-old in question won’t be able to find whatever it is you are looking to hide. ---
**Author:** ![Gary\_Robson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gary_robson/32/3448_2.png) [@Gary\_Robson](https://boards.straightdope.com/u/Gary_Robson)\ **Post date:** [April 22, 2006, 6:53pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/25 "2006-04-22T18:53:17Z")
If you’re worried about the kind of file recovery programs that people use at home (as opposed to techniques that require a laboratory), there’s a simple method of wiping clean: 1. Erase everything that you really want erased. 2. Put one really big file on the drive (a movie, for example) 3. Copy it several times, then select all the copies and copy those. Repeat until you run out of hard disk space. 4. Erase the files from steps 2 and 3. If you’re really paranoid, repeat the process with another file of a different size, or with your entire collection of music files. The point is just that other data is being written over the files you erased in step 1, making it much harder to recover. ---
**Author:** ![jayjay](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jayjay/32/6765_2.png) [@jayjay](https://boards.straightdope.com/u/jayjay)\ **Post date:** [April 22, 2006, 6:58pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/26 "2006-04-22T18:58:27Z")
[QUOTE=InvisibleWombat] 2) Put one really big file on the drive (a movie, for example) [/QUOTE] Just make sure it’s not porn. That would be embarrassing. “What’d you find about that hard drive we confiscated?” “Well, she apparently has a thing for “Rear Entry Rhoda”. She had 15 copies of it on her hard drive.” ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [April 22, 2006, 7:05pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/27 "2006-04-22T19:05:41Z")
[QUOTE=cbarnes] Not even degaussing the drive will truly make the data unrecoverable [/QUOTE] Not true. However, you need a REALLY strong field to successfully degauss the drive platters, because the head assembly housing itself provides an effective level of magnetic shielding against externally-applied fields. An ordinary tape or diskette degausser is NOT sufficient for the task, unless you open the case and expose the platters–which will more than likely destroy the drive anyway, unless you have access to a clean room. However, if you DO manage to successfully degauss the media, you will have also succesfully erased the low-level formatting; this will effectively render the drive inoperable until you perform a low-level format. Most drive manufacturers can provide a utility to do just this. Once you’ve done this, though, all data that was once on the drive will be completely and irrevocably unrecoverable. ---
**Author:** ![mks57](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@mks57](https://boards.straightdope.com/u/mks57)\ **Post date:** [April 22, 2006, 8:00pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/28 "2006-04-22T20:00:27Z")
I’ve successfully used “Darik’s Boot and Nuke” to sanitize the hard disks in PCs. [http://dban.sourceforge.net/](http://dban.sourceforge.net/) It’s free software. You can use it to make a bootable floppy or CD, so it doesn’t matter what, if anything, is installed on the PC that you want to sanitize. It’s much better than messing around with fdisk/format/DiskManager. ---
**Author:** ![Gorsnak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gorsnak/32/7587_2.png) [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)\ **Post date:** [April 22, 2006, 8:07pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/29 "2006-04-22T20:07:41Z")
[QUOTE=black455] The only surefire way to get rid of everything involves a sledgehammer, an MRI machine, and a pit of lava. [/QUOTE] I would think an oxy-acetylene torch would be more than sufficient all by itself. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [April 22, 2006, 8:09pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/30 "2006-04-22T20:09:45Z")
[QUOTE=Gorsnak] I would think an oxy-acetylene torch would be more than sufficient all by itself. [/QUOTE] Or a screwdriver and some steel wool. ---
**Author:** ![mks57](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@mks57](https://boards.straightdope.com/u/mks57)\ **Post date:** [April 22, 2006, 8:16pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/31 "2006-04-22T20:16:38Z")
[QUOTE=Q.E.D.] However, if you DO manage to successfully degauss the media, you will have also succesfully erased the low-level formatting; this will effectively render the drive inoperable until you perform a low-level format. Most drive manufacturers can provide a utility to do just this. Once you’ve done this, though, all data that was once on the drive will be completely and irrevocably unrecoverable. [/QUOTE] Modern hard drives can’t be low-level formatted by the end-user. Degaussing the platters will wipe out the embedded servo data that is used to position the heads. You need a special servo writer machine to write the servo data on the platters. A properly degaussed drive is just scrap metal. I know someone who degausses hard drives before they are sent to the recycler. He uses an industrial-strength degausser that is far more powerful than anything someone is likely to have around the home or shop. The room that it’s installed in has prominent warnings on the doors about not entering the area if you have a cardiac pacemaker. It takes a tremendous amount of power to degauss modern high-coercivity media. ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [April 22, 2006, 8:41pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/32 "2006-04-22T20:41:16Z")
[QUOTE=mks57] Modern hard drives can’t be low-level formatted by the end-user. Degaussing the platters will wipe out the embedded servo data that is used to position the heads. You need a special servo writer machine to write the servo data on the platters. A properly degaussed drive is just scrap metal. I know someone who degausses hard drives before they are sent to the recycler. He uses an industrial-strength degausser that is far more powerful than anything someone is likely to have around the home or shop. The room that it’s installed in has prominent warnings on the doors about not entering the area if you have a cardiac pacemaker. It takes a tremendous amount of power to degauss modern high-coercivity media. [/QUOTE] Yep.. that’s true the “wipe & restart” format utilites provided by disk manufs for IDE drives are not “real” low level formatting utilities, although some disk manuf online help desk service people incorrectly call them that. ---
**Author:** ![Rhythmdvl](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rhythmdvl](https://boards.straightdope.com/u/Rhythmdvl)\ **Post date:** [April 22, 2006, 9:08pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/33 "2006-04-22T21:08:25Z")
[QUOTE=chrisk] Why does fdisk have an f in it? I’m not sure on that one.) [/QUOTE] I thought fdisk = fix disk, as in fix things in position for formatting. Anyone? ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [April 22, 2006, 9:17pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/34 "2006-04-22T21:17:09Z")
[QUOTE=Rhythmdvl] I thought fdisk = fix disk, as in fix things in position for formatting. Anyone? [/QUOTE] [fdisk command](http://www.computerhope.com/fdiskhlp.htm) ---
**Author:** ![Valgard](https://avatars.discourse-cdn.com/v4/letter/v/7feea3/32.png) [@Valgard](https://boards.straightdope.com/u/Valgard)\ **Post date:** [April 23, 2006, 12:28am UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/35 "2006-04-23T00:28:58Z")
I’ll ditto the suggestion for DBAN (Darik’s Boot And Nuke) - very simple to make a bootable CD which you then boot the PC from and follow the onscreen commands. This is good against normal “undelete” software. Also ditto on the cautions r.e. degaussing a hard drive. At work we have a pretty hefty tape degausser (used to erase backup tapes before they are put back into rotation) and I tried it on a laptop hard drive one time - pull drive from laptop, put it on the degausser, fire up degausser, spin drive around (makes horrible rattling noises as the platters jiggle around in the magnetic field), put drive back into laptop. Turn laptop back on. Laptop boots up normally, zero apparent damage or data loss. ---
**Author:** ![asterion](https://avatars.discourse-cdn.com/v4/letter/a/4da419/32.png) [@asterion](https://boards.straightdope.com/u/asterion)\ **Post date:** [April 23, 2006, 1:23am UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/36 "2006-04-23T01:23:28Z")
[QUOTE=Myglaren] Reformatting can leave recoverable traces for anyone sufficiently interested and skilled to want to bother but is effective enough for most purposes. Fdisc-ing is better and removing partitions and repartitioning an improvement on that. Reinstalling the OS and office software will go a stage further in overwriting any remaining data. Given the right tools it is possible to recover data that in theory has been wiped. [/QUOTE] When I really want to wipe something, I use Eraser and overwrite the sectors 35 times with random data. I don’t know if I’d want to do it with a modern hard drive, as wiping a 100 GB drive would mean writing 3.5 terabytes of data. That’d take a while. ---
**Author:** ![FlyingRamenMonster](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@FlyingRamenMonster](https://boards.straightdope.com/u/FlyingRamenMonster)\ **Post date:** [April 23, 2006, 3:02am UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/37 "2006-04-23T03:02:16Z")
[QUOTE=Q.E.D.] Or a screwdriver and some steel wool. [/QUOTE] That’s what I came in here to say. Screwdriver through the disk platters, and $100 for a new hard drive. ---
**Author:** ![chappachula](https://avatars.discourse-cdn.com/v4/letter/c/d2c977/32.png) [@chappachula](https://boards.straightdope.com/u/chappachula)\ **Post date:** [April 23, 2006, 2:21pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/38 "2006-04-23T14:21:59Z")
[QUOTE=FlyingRamenMonster] Screwdriver through the disk platters, and $100 for a new hard drive. [/QUOTE] I’ve heard (urban legend?) that if you put a hard drive in the oven and heat it up to 500 degrees, the disk warps and becomes non-readable. anybody know if it’s true? (I dont usually bake computer disks, but my last batch of cookies burned, so it got me thinking…) ---
**Author:** ![mks57](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@mks57](https://boards.straightdope.com/u/mks57)\ **Post date:** [April 23, 2006, 2:30pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/39 "2006-04-23T14:30:58Z")
[QUOTE=chappachula] I’ve heard (urban legend?) that if you put a hard drive in the oven and heat it up to 500 degrees, the disk warps and becomes non-readable. anybody know if it’s true? [/QUOTE] Sounds like a really bad idea. There are all sorts of materials in a hard drive, many of which can burn or emit harmful vapors. Magnetic materials have something called the Curie temperature, above which they lose their ability to be magnetized. So heat is one way to erase media. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [April 23, 2006, 3:17pm UTC](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749/40 "2006-04-23T15:17:58Z")
[QUOTE=cbarnes] If you _really_ don’t want the data found, you should toss the drive into a woodchipper because destroying the drive is your only guarantee of unrecoverable data. [/QUOTE] Sadly, I see this sort of advice given all the time. And as a result, many folks find themselves having to get their woodchippers repaired or replaced. People, woodchippers are made for chipping _wood_! They do not mesh well with current computer components (unless said computer components are made of wood), and I cannot condone their use as harddrive chippers. Personally, I blame “Fargo” for this phenomenon. [Previous page](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749.md?page=1) [Next page](https://boards.straightdope.com/t/how-do-i-completely-delete-everything-from-my-computer-in-one-fell-swoop/353749.md?page=3)