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Reformatting and reinstalling an operating system will, by the very nature of "reformat," erase all the data on your computer. Yes, everything will be erased. You will need to backup.

A few days ago, my five-year old HP desktop PC would not boot up. I took it to a computer repair shop and they said all of my info was still on my hard drive and it needed the Vista operating system reinstalled. She said that I would lose all of the information on my hard drive during the reinstallation. I don't understand why that would happen. Is that the way it goes or were they just trying to add more income by backing up the hard drive before reinstalling the operating system? Thanks!

In this excerpt from Answercast #25, I talk about the steps involved in reformatting a hard drive and reinstalling Windows... first, and most important, is to backup... as everything will be erased.

Reformatting will erase your data

It is, in fact, just the way it goes. A proper reinstallation of Windows does in fact erase everything that's on the hard disk that contains Windows.

That's the best way to make sure that Windows itself is installed completely cleanly and anything that's causing problems is thoroughly removed.

Backup yourself

Now, you didn't have to pay them extra to back up your hard drive because in all honesty: you should have been backing it up yourself.

Backing up regularly is important for many, many different reason. Saving a little money at the PC repair shop is only one of them. So, what I suggest you do is that you start now... before you take the machine to the repair shop.

Get yourself a copy of a good backup program, (I recommend Macrium Reflect) and take an image backup of your system. That way, you'll have a copy of everything that's on that hard disk right now.

Then, go ahead and let them reinstall Windows. When you get it back, you may need to reinstall a few applications that they weren't able to reinstall for you, but you will have your data. You'll be able to copy your data back from the backup that you took before Windows was reinstalled.

How to reformat and reinstall

In fact, even when you do this yourself, the complete reinstallation process is:

  • Backup

  • Reformat

  • Reinstall Windows

  • Reinstall your applications

  • And then reinstall your data.

It's all based on having a good image backup of the machine before you start the process.

Backup regularly

Now that you've got backup software, make sure that you're backing up regularly because you don't know when your hard drive might die or when a virus might infect your machine.

Having a backup will protect you from all those kinds of things. If any of them happen without a backup, you are at risk of losing everything on your machine. I don't think you want to do that.

So, get in the habit of backing up and that way, not only will you save a little bit of money at the PC repair shop, but you'll actually save a lot of hair pulling should that machine ever die without having a backup in place.

Article C5442 - June 10, 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.

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