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How Do I Get the Password for a Computer I Purchased at a Garage Sale?

Question: I purchased a computer at garage sale but they did not know main password. Is there a way I can get this free? Hope I did not throw my money away.

I’m going to assume that by “main password” you mean the Windows log-in password.

I’ll show you how you can bypass that on most computers and set your own – it’s really not that hard.

Then I’ll tell you why you really don’t want to do what I suspect you’re planning to do.

You probably have a very useful machine, even if you can’t log in to it right away.

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The used computer

To clarify the scenario a little, you’ve just picked up a previously owned computer.

The machine has some version of Microsoft Windows already installed on it, presumably belonging to the previous owner. It’s asking you for a log-in password, and of course you don’t know what that is.

To answer your immediate question: I can’t get you the password, but you can probably set your own. This article will walk you through the steps to reset the administrator account password and gain access to the entire Windows installation: I’ve lost the password to my Windows Administrator account, how do I get it back?

Having said that, I strongly advise you not do so.

Fear of the unknown

Questionable DesktopHere’s the problem: you have no idea what’s on that machine.

Sure, it has Windows.

It could also have lots and lots of malware. The machine could be thoroughly infected with viruses and spyware.

Or worse.

And even with all the anti-malware tools in the world, there’s simply no way to know – I mean really know – if you’ve successfully cleared it of all infections.

Obligatory legal weaseling

I also have to point out that taking that copy of Windows as your own may actually be illegal. (And of course, the obligatory caveat: I’m no lawyer; this is just my personal understanding of the landscape.)

Many machines – particularly OEM machines purchased directly from a manufacturer with Windows pre-installed – come with a license that restricts that copy of Windows for use on that specific machine only, and quite possibly only to the original purchaser.

There are many variations on Windows licensing agreements, and they’ve certainly changed over time, but it’s yet another reason to consider a safer approach.

The safer approach

The only practical thing to do, and the only safe thing to do, is this:

  • Run a tool like DBAN to completely erase everything on the hard drive.
  • Reinstall Windows from scratch.

That means either you need to have the Windows installation media that came with the machine when you purchased it (if the license allows for that transfer of ownership), or you should plan on purchasing a new copy of Windows to be installed on that machine. (If the cost is prohibitive, you might also look into free alternatives like Linux.)

Do not rely on pre-installed Windows on a used machine. It’s not a way to get Windows, and it’s simply not safe.

The view from the other side

As I said, you don’t know what’s on that machine. It could have tons of illegal content on it, malware, or … it could have sensitive data that the prior owner should have erased.

Don’t be that prior owner.

When it comes time for you to dispose of a machine, make sure to completely erase the hard disk before getting rid of it. Once again, DBAN is my recommendation.

Too many machines found in flea markets, garage sales, or on Craigslist accidentally have buckets of personal and sensitive information the prior owner simply “forgot” to remove.

Don’t be that person.

Do this

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36 comments on “How Do I Get the Password for a Computer I Purchased at a Garage Sale?”

  1. Why can’t one just boot into DOS and run “FORMAT C:” ?

    Well, if you want to boot from C: and run a DOS command from there you’d need to login first, which by definition we can’t.

    If you happen to have some other way to boot into DOS (like a floppy), then by all means, go for it, with the caveat that:

    Format doesn’t securely erase data. The things that were on the disk before the format run the risk of re-discovery. For most people that’s not an issue.

    Finally: if you reinstall Windows (as you should), that’ll have the option to do the reformat for you, so if Format is good enough then the extra step isn’t really needed.


  2. Good answers here Leo but I think one thing is missing. Perhaps the user is not referring to an OS (that is to say, a Windows) password.

    If the PC won’t boot without a password, or the user cannot change the boot order without a password then of course we’re talking about another animal. This BIOS password for nearly any system can be erased by removing the battery (a small flat disc typically featuring a + or -) from the motherboard. Replace it and power on, the password should no longer be intact.

    • Geoff, thank you, I’m going in for the battery, such a simple answer to a big headache. I should have thought of it, I guess sometimes you just have to think inside the box. Appreciate the common sense.

      • Nevermind, it was too much of a hail mary, didn’t work, neither does troubleshooting and resetting, I’ve taken every pro who answers this question and used their advice. This is my computer, which I got to replace the computer I built myself after getting certified in computer repair as a tech. But, my Windows 8 had to be upgraded to Windows 10, due to my inability to stop driving my debt. up and again going to school. But my nephews porno addiction and Windows 10 decided I don’t need to live in today’s world, therefore my computers either have internet but won’t give me a break on forgetting a password to access them. Or my wonderful still working and access allowing laptop let me use the offline stuff that I can save files to, but that’s it, they don’t recognize a wifi internet access. If the workforce wasn’t so adamant about applying for a job via the websites and borrowing someone else computer for 2 hours while trying to fill out an application, this would actually be funny. But, it’s to the point where I’m just waiting and drinking and tired now. So, maybe one more try at pulling the battery, maybe while the power is on, so it knows that I pulled the battery. I got nothing to lose, what my computer won’t work? Now, that’s funny!

        • Pulling the battery with the power on wouldn’t help. It’s not a matter of the computer recognizing that the battery is out. Pulling the battery and leaving it out for a period of time sufficient for the circuits to discharge (sorry, I have no idea how long, but I’d wait at least an hour) any residual charge might work. In fact, it’s possibly the opposite. With the power on the CMOS memory might even continue to receive current and not discharge.

          I also wouldn’t recommend doing any work on the motherboard with the power on. There’s a risk of short-circuiting the machine.

  3. I have a used IBM computer that I purchased from a professional computer repairman. It has worked fine for years with its original copy of Windows XP Professional. The only thing I’ve found that should not be in it is the drivers for a Canon scanner, installed in 2002.

  4. With all respect to other people’s views, I wouldn’t wipe out what’s on the drive until I explored it.I just don’t see things in black&white.Why not explore it with a bootable CD like LiveXP from Winbuilder -1st entry ,which leads here
    or Ultimate Boot CD for Windows . There are many others,like BartPE based or Hiren’s boot CD etc
    Run a virus scan ,explore the contents, retrieve the product keys etc.Only if not acceptable would I totally wipe it.Otherwise ,just use what’s there. ;)

  5. Crazy paranoia will put you in the loony bin. Most S/H computers will have nothing more than a few nasties ( spyware and viruses ), and some silly files, like letters to aunt Sally. The first you remove with standard security programs, and the second you delete, then run erase unused disc space with Eraser, to completely remove all traces of the previous owners documents.
    Now you have a clean computer, but be smart and get the license key ( often a sticker on the box ), and driver details, so you can reinstall XP. The cops will not prosecute you for having kiddy porn on a machine you innocently bought, especially if you tell them about it, which you won’t, because they will promptly impound it as evidence.
    My tech friends do this all the time, and have never had any problems. Leo and other are only telling you the worst case scenario, if you don’t do the above.

    Regards Bill3.

  6. If the computer has a legit coppy of Windows{sticker should be on the case somewhere with number} all is well to borrow a copy of Windows DVD from a friend {same edition} and reinstall using the number on your sticker when asked. If any problems ring up activation and answer a few easy questions and you should be in business.
    You can also do a full format in ntfs if you prefer although any preinstalled software will be deleted.
    Cracking password info will not be found on this site for obvious reasons..I recall reading somewhere.


  7. If you can boot to recovery options in cmos or bios and reinstall to Factory conditions without saving any personal files & settings, would this be considered safe & legal? I’ve done this with older laptops a few times then sold them cheap at our community yard sales. I did activate windows after the reinstall.

    • We’re not lawyers, so wouldn’t speak to the legality of reselling the Windows agreement that way. Looking at it technically the worry would be that the reinstall didn’t completely wipe the disk and that some personal information might be left. Kind of nitpicking for sure. But security geeks are nitpickers!

  8. One consideration about re-loading Windows on a second hand machine, particularly a laptop, is obtaining the correct required device drivers for the machine. If you don’t have Restore Media, as is often the case nowadays, finding the correct device drivers on a manufacturer’s web site is often not easy. I’m sure that this is done on purpose.

    • Quite correct about drivers ..this was always the biggest bugbear I found for lots of older computers acquired second hand after a reinstall of Windows.
      There is a work around however.
      Use a boot disc like Live xp then a program called Double Driver, save the drivers to a flash drive.
      Win 7 has most drivers included..widows XP has some but often no network and sound or added video/graphics cards for example.

      • I boot from Mini XP which is included in Hiren’s Boot CD . I then use Double Driver which is free.
        Drivers from other Windows Systems will be backed up if required. Just direct to Windows if DD can’t find installed drivers.
        This method is only useful if original drivers are installed in the first place.
        Handy for computers which will not boot normally and a reinstall is required.

  9. I purchased a dell core i5 computer at a garage sale. ($10) Has xp pro on it, But the stickers are Win7 pro. Anyhow, I can’t get past the corporate login screen, but it boots to xp rather than win7. It has 4 gigs of ddr3 memory, so I’m wonderin which would be the best way to go. Have both Dell XP pro, and win 7 pro discs somewhere……Just moved down to Tasmania from Queensland and had to move again when the right house came up for sale… I’ll have the discs somewhere …when I actually find them. Corporate security is something I just haven’t the smarts to get around! Looks like a clean install sooner or later so I can actually use the thing!
    Thanks for the prudent counsel all you counsellors

    • There’s no way to be sure if Win 7 will accept the license on the sticker. The safest way to find out is to do a system image backup of your XP system so you can restore if it doesn’t accept the license.

        • There’s nothing for you to clean. It’s part of the installation process. When you install Windows from the installation media (USB Flash drive or DVD), it asks you if you want to keep the previous installation and update it. At that point, choose clean install or something like it.

  10. How can I use any correction discs if I can’t get on line because of password problem? { I’m on a different computer now]

  11. I have the answer, if you bought one that has a user account already, and don’t know the password, this is how to factory reset if f9 doesn’t work. At the log in screen, hold shift and navigate to restart, it will bring you into factory reset mode!!

    • Wow!!! I’ve tried every suggestion on the planet and yours was the only one that worked. Sending you virtual hugs and kisses. XOXO

      -Shelly from Atlanta

  12. I purchased a 2016 Dell desktop computer, it was purchased from a deceased man family they have the login pw but no ministrator pw to change any settings? ?? Help! It let me add my name to the login settings but it will not login under me when I restated the computer just his name and pw HELP!

  13. I recently purchased am old dell home computer at the 2nd hand shop. It has an admin.lock on it. Is there any way to reset it or have i wasted my money.?

  14. Hi thanks so much for this info. I came across a discarded HO laptop with Windows 7. The only thing I want it for is to watch DvDs so not interested keeping Windows. I’m not technically savvy but know enough to follow along so what is the procedure to install Linux if I can’t log on? Another dumb question is where would I get Linux? I’m I right to assume I have to burn to a disk? If so, is it difficult to install like needing to do a number of command prompts?
    Again sincere thanks for having such an informative site

  15. Hi Pat here again. I just did some sleuthing and found the Linux site which has install instructions. It also directed me to

    So my question now is how to choose which Linux to buy so I can access the laptop someone discarded. Money is tight so would appreciate knowing whether one for 5.95 would be suitable or whether paying 14.95 is better value in the long run. I only need a computer to watch dvds and surf the net. I don’t play games.

    My desktop runs XP and may soon give up the ghost so it might be handy to have this laptop as a backup so I would need Linux to do those two things.

    Thanks again. Happy New Year!

  16. now gettig the option to continue to wind 10 it is runnig 7 i thought or says i can troubleshoot and reset pc


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