Helping people with computers... one answer at a time.

It's not difficult at all to gain access to a used computer running Windows without knowing the password. You just don't want to.

I purchased a comp 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'll assume you mean the Windows login password.

I'll show you how you can bypass that and set your own - it's really not that hard.

And then I'll tell you why you really, REALLY, REALLY don't want to do what I suspect you're planning to do.

To clarify the situation, you've just picked up a used 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 login password, and of course you don't know what that is.

"Do not rely on pre-installed Windows on a used machine. It's simply not safe."

To answer your immediate question: I can't get you the password, but you can set your own. This article will walk you through the steps to reset the administrator account 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...

Don't do it!

Here'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 - that the machine has been cleaned up.

The only practical thing to do, 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 that either you'll have wanted to make sure to get the Windows installation media that came with the machine when you purchased it, 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 Ubuntu Linux.)

Do not rely on pre-installed Windows on a used machine. It's simply not safe.

Side Note: An Important Lesson

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. Too many machines found in flea markets, garage sales or on Craigslist accidentally have personal information that the prior owner simply "forgot" to remove.

Use DBAN before you get rid of your old machine.

Article C4287 - April 29, 2010 « »

Share this article with your friends:

Share this article on Facebook Tweet this article Email a link to this article
Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

April 30, 2010 3:14 PM

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.

Another computer user
May 1, 2010 9:04 AM

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.

Keith W. Jordan
May 4, 2010 11:54 AM

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.

Robin Clay
May 4, 2010 3:36 PM

... or that computer may be full of illegal porn, and the cops may come and lock you up...

May 4, 2010 4:48 PM

I personally think the best way to remove data is to bash up the hard drive. :-)

Richard in Dallas
May 4, 2010 5:04 PM

Hereís what I would do:

Option 1. Open the PC case, take the original hard drive out and put a brand new one in and install Windows on the new hard drive. Take the old hard drive to the rifle range and use it for a target; make sure you hit it. Or think of some other way to destroy it.

Option 2. Install Windows over the existing windows on the original hard drive. When you get to the format disk option, take the complete format (I have forgotten exactly what Microsoft calls it.) Do not use the quick format. The long format SHOULD erase everything on the hard drive, even Linux files.

Option 3. Download the Windows 98SE Emergency Boot Disk from the Internet or create it from a Windows 98SE PC; Start => Settings => Control Panel => Add/Remove Programs => Startup Disk tab.
Reboot using the Emergency Boot Disk.
Then run FDISK and reformat the hard drive.

I personally wouldnít use the original hard drive that came with the PC. Itís probably near the end of its useful life.

May 4, 2010 5:52 PM

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. ;)

May 4, 2010 6:00 PM

Try and get a new harddrive and attached that to the computer, use the pin to the original hard disk, reset it so that it becomes slave to your new harddrive. try and access your old hard driver using you new drive if you care.

May 4, 2010 8:21 PM

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.

May 4, 2010 9:29 PM

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.


May 11, 2010 2:13 AM

I recommended try to Step 1: Start Windows PC
Step 2: When you can see the Windows login screen, press ctrl+alt+del keys Twice and it'll show Classic Login box
Step 3: Type Administrator as Username and leave the Password field blank
Step 4: Press the Enter Key and then you can be able to login the default windows administrator account which is it created by default when install windows.

Note: When you input the key combination Please donít put the cursor on any account. And if you change the name or password before, you cannot login by this way.

more free windows password recovery way refer to

May 31, 2010 8:36 PM

You can login in administrator account to delete your username or password.

Or you using Windows Password Unlocker to reset your user password.

April 5, 2012 5:52 AM

I bought a used computer and can't get the previous owner password and user to log on further.

I'd recommend re-reading the article you just commented on. It addresses your question.

Comments on this entry are closed.

If you have a question, start by using the search box up at the top of the page - there's a very good chance that your question has already been answered on Ask Leo!.

If you don't find your answer, head out to to ask your question.