How to reinstall Windows 10 (without data loss)

Reinstalling Windows is almost always a headache for inexperienced users, especially if there are a lot of necessary documents on the disk (and there are always a lot of questions on this topic …).

In order to structure these questions somehow, I have combined them into this one note, in which I will give some of the most typical ways how you can reinstall 10 without losing documents, pictures, music and other ‘good’ on the disk.

It is worth noting that in the article I will proceed from the fact that your hardware is working properly, and all the ‘problems’ with the current OS are of a programmatic nature (for example, you accidentally deleted some system files, installed an unsuitable driver, were exposed to virus infection, etc.).

Now closer to the topic.


I get quite a lot of questions about what to do next: how to transfer documents, files, programs from the old Windows to the new one, as well as how to safely remove one of the two Windows OS on the computer. On this topic


The content of the article

  • 1powers to reinstall the OS and not lose documents and files
    • 1.1If the installed Windows does not boot
    • 1.2If the installed Windows still ’somehow’ works
      • 1.2.1Using backup (external disk cloud)
      • 1.2.2By creating another partition on the disk
      • 1.2.3Via update (built-in function)

Ways to reinstall the OS and not lose documents and files

If the installed Windows does not boot

In this case, I would suggest to start by trying

If the recovery was unsuccessful - then, as an option, I would advised

Let’s look at how this is done…



To get started, you will need 2 flash drives (from 8 GB) and a working computer connected to the Internet (you can ask for a friend / neighbor, etc.


  1. to create
  2. to create

Typical LiveCD / What programs are on the ‘Sagittarius’ disk…’



Next, we need to boot from a LiveCD flash drive on a problematic computer. To do this, it’s enough to ‘tweak’ the BIOS a little or use the Boot Menu (if you don’t know what it’s about - see the link below to the instructions).

How to configure the BIOS (UEFI) to boot from a flash drive or disk (CD/DVD, USB, SD)



In Windows, which we started with a LiveCD flash drive, you need to open’Disk Management’(Win R–

Next, on one of the HDD/SSD partitions (on which there are 20-30 GB available), you need to click the PCM and select the option’Compress the volume’. Example below.

Note: this operation does not delete or damage the data on the disk (unless, of course, you have some problems with the file system …).

Disk management - compress volume

After that, you need to click ‘Next/next…’ and specify the space for the new partition (minimum: usually requires about 25-35 GB).

Place for a new section

Literally in 10-15 seconds. you will see that another unmarked partition has appeared on the disk (marked in black). Create a simple volume on it.

Create a simple volume

And format it into the NTFS file system (you can assign any unoccupied drive letter…).

Format by default

As a result, the disk will now be 2 sections:

  • One: ‘C:’ with Windows (which was originally),
  • second: ‘H:’ (new volume). On this section, of course, there is no data yet…

new volume



Now this ‘problematic’ You need to turn off the PC and connect another USB flash drive to it - the installation one (with Windows 10).

After, enable, go to

How to boot from a USB flash drive or external HDD -instructions for beginners

Boot Menu - start the OS installation

Then start installing Windows OS.

Install the OS

Important point:

Custom installation


Choosing our section

Next, the steps are standard and of little interest: the choice of region, language, etc. (they do not affect the key task in any way).

Typical OS installation

Upon completion of the installation, you will have 2 sections:

  • one has a working Windows 10 OS,
  • on the second - the ‘old’ OS and all your data (by default they are in the folder ‘C:Usersalex ‘(alex is your account name)).

The new OS is working - we transfer everything we need

Problem solved?!


If the installed Windows still ’somehow’ works

Using backup (external disk cloud)

I will not be original, but the most reliable and easiest way to 100% save your files and documents (for any problems with the PC) is to backup them to an external hard drive (now there are relatively inexpensive models for 250-500 GB on sale - the very thing for such cases …).

How to order a product on AliExpress with a discount (purchase in an online store with savings)

External HDD is connected to USB

By default, all user folders are located in the following path:

  • C:UsersalexDesktop - desktop,
  • C:UsersalexDocuments - documents,
  • C:UsersalexPictures - pictures,
  • C:UsersalexVideos - video,
  • C:UsersalexMusic - music.

The alex will be your account name.

By the way

Yandex Disk:how to use it, upload and download files, photos. How to set up auto-creation of a copy of my documents

The Yandex Disk program is installed on Windows



By creating another partition on the disk

As a rule, all new PCs/laptops usually have 1 logical partition for 1 physical HDD/SSD, on which Windows is installed.

To make it clear what we are talking about, open disk management (this is a regular Windows utility). To do this, click Win R and use the diskmgmt.msc.


Pay attention to the screenshot below

The essence of what we will do:

Disk management / as a reference

How to create another partition on disk:

1) I will show the example of the Windows partition ‘C:’.

To begin with, you should have free space on it (for example, I’m going to ‘pinch off’ from the ‘C’ section:’ 30 GB means free space on ‘C:’ must be more than 30 GB).

And so, in disk management, right-click on the ‘C’ section:’ and select the option’Compress’.

Compress the volume

2) Next, specify the size of the volume you need (note: 30 GB is about 30,000 MB).


3) After compression, an unallocated area should appear on your disk (marked in black). Right-click on it and create a simple volume.

Create a simple volume

4) Specify the NTFS file system and format this partition. An example is shown in the screenshot below.

Formatting a new volume

5) As a result, you will have a new partition for further OS installation. In my example, this is the ‘E:’ section.

A new section has been created


Custom installation!

And specify exactly the partition that we created earlier (in my case it is 29.3 GB (the same ≈30,000 MB)).

Selecting a disk for installing the second OS

Actually, when the new Windows is installed - when you turn on your PC/ laptop, you will start to have an additional one. a window in which you can specify which OS to load.

Select the OS (how the menu will look when you turn on the PC)

Then you can slowly transfer files and documents to the new OS, and subsequently delete everything unnecessary on the partition with the ‘old’ Windows…

In my humble opinion, this method is very convenient both for replacing the old ‘buggy’ version of the OS, and for testing some interesting assemblies.


Via update (built-in function)

In Windows 10, there is a special option to restore factory settings while saving all files and programs (i.e. you will have a ‘fresh’ clean OS, which happens after reinstalling with formatting).

The idea of the developers seems to be not bad, but immediately I want to mention

Now about how to run it.

Option 1

1) Go to Windows Settings.

Start - parameters

2) In the section’Update and Security/Restoration’click on the button’Start’ (tab ‘Return the computer to its original state’).

Recovery - start

3) Choose an option’Save my files’. Next, the reinstallation process will start, which will take 10-20 minutes. time*.

Save my files

Option 2

If your Windows has stopped booting, as an option, you can use a bootable USB flash drive. After starting the installation and selecting the language (see the screenshots below), specify what you need’Update: Installing Windows with saving files, settings and applications’.

Start installing Windows 10

It is worth noting that this type of installation may not be available in some cases (then see the previous options proposed in the article).


The best free programs in Russian for Windows: my basic set for a new PC.


Comments and additions to the topic are welcome!

All the best!


First publication: 14.09.2019

Correction of the note: 30.05.2020

Useful software:

  • Video Editing
  • Excellent software for creating your first videos (all actions follow the steps!).
    Even a beginner will make a video!

  • Computer accelerator
  • A program for cleaning Windows from ‘garbage’ (removes temporary files, speeds up the system, optimizes the registry).

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