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It's impractical to try and erase everything on a hard drive except the operating system. Fortunately, there is an better solution.

What's the best way to clear my hard drive of everything but the operating system? In this case, Windows XP, SP3.

In this excerpt from Answercast #34, I look at the difficulties involved in trying to erase everything on a hard drive except the operating system. Our old standby, reformat and reinstall, will do the trick.

The operating system

Unfortunately, there is no way to clear your machine of everything except the operating system.

The problem is that programs that have been installed over time kind-of blur the line of where the operating system begins and ends. Windows is pretty poorly designed in that sense. There are many things that make it difficult to understand exactly what is and is not part of the operating system.

  • A good example is Internet Explorer.

We don't think of Internet Explorer as being part of the operating system. We think of it as being a standalone application in its own right. Yet, many components of Internet Explorer are actually used by Windows itself.

Reformat and reinstall

So, since there is no way to do exactly what you're asking for, the only solution I can offer is to do the traditional:

  • Reformat your machine completely (in other words, erase everything including the operating system);

  • And then reinstall the operating system from scratch.

That's really the only way to insure that the only thing on your machine is the operating system.

Securely erase the drive

If you're concerned about files possibly being recovered, you might consider using DBAN: Darik's Boot and Nuke. That is used to securely erase the entire hard disk, eliminating all traces of any files that might have been there.

  • Do that before you install Windows again from scratch.

Your only option

Unfortunately, as I said, there really isn't a way to do exactly what you're asking for. The only way is to erase everything and reinstall the OS from scratch.

Article C5574 - July 12, 2012 « »

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?

July 13, 2012 9:25 AM

this was great. i`ve been wanting to do a clean re-install. now tell me how to do it on a second hand PC that did not come with a CD.

July 13, 2012 9:34 AM

@Glen - Sometimes you can request and receive an OS copy from the manufacturer, but if that is not possible I would borrow a CD from another machine (one you have or friend's or colleague's etc.) with the same version OS and reactivate with the code on your machine.

July 13, 2012 9:54 AM

What about using a tool like ccleaner to delete the empty space on your drive? Say you have a pc you wanted to donate, you remove any 3rd party software using add/remove or Programs/Features and then running the ccleaner wipe on unused hard drive sectors overwriting deleted data. Granted, I'd rather format and reinstall but for someone not comfortable with that, is there any reason you would not use this technique?

July 13, 2012 11:20 AM

If you think that you may need to clear your hard drive back to the OS on a more regular basis, you might want to take an image of your hard drive after you reformat and reinstall and set your Windows settings. Then you can just use the system image.

Mark J
July 13, 2012 12:02 PM

That technique could possibly miss some data which is in a file that you overlooked deleting. CCleaner only cleans temporary file, free space and internet browser files.

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