Over the years, experience teaches us that every Windows installation deteriorates, no matter how thorough our maintenance. In previous articles we explored the possibility of restoring the operating system, but if you think the performance loss is too great or the computer no longer responds, you'll need to do what people colloquially call format Windows 10. Where do we start?

Format Windows 10

"Format Windows 10": What exactly do you want to do?

The classic example is a hypothetical person who leaves a laptop on your desk and asks you to "format Windows." The request immediately causes confusion because deep down we know that Windows isn't formatted, but rather reinstalled. However, this isn't the first time something like this has happened, and it won't be the last. We prepare the tools, warn about data loss, and the user suffers an emotional crisis ("I have 10 years of files and I can't delete anything, oh my God!"), back and forth... and Windows goes flying.

Now, let's imagine you want to do this process yourself, involving Microsoft's latest operating system. The decision to "format Windows 10" may be due to an installation that's too old (Windows 10 has been on the market for over half a decade), a major update that got interrupted, an error that resists our best repair attempts... the list goes on. Inevitably, you need four essential resources:

  1. A working Windows environment (it can be the same computer to be cleaned, or another).
  2. A stable internet connection to download the Windows 10 ISO image.
  3. A copy of the program called Rufus, which has a portable version.
  4. A USB flash drive with 8 gigabytes of capacity or more.

How to prepare a Windows 10 USB drive

The Rufus interface. Note the difference in the button; we explain the change below.
  1. The first step is to create the installation USB drive, and for that we download the portable version of Rufus by visiting its official page. A huge advantage of Rufus is that it has a mechanism to automatically and securely download the Windows 10 ISO image. Keep a copy of Rufus on the desktop or in another folder if you prefer.
  2. When Rufus runs for the first time, it will ask permission before checking for online updates, to which you should reply 'Yes' so it can get the Windows 10 download script. This will create a small .ini file next to the Rufus executable; don't worry about it.
  3. Connect the USB drive (remember, 8 GB minimum), and Rufus will detect it immediately (if not, try another USB port or another drive). In the top right corner, you'll see a small arrow next to the Select button. Click it, change the option to Download, and click the button. Rufus will download the appropriate script.
  4. The new options menu is easy to navigate: Select Windows 10 as the operating system, followed by the latest release available (unless you need an earlier build), the Windows 10 edition (Home/Pro is the norm), the language and the architecture (unless the computer is very old, you should choose x64). If you want to download the image using a browser, check the box. Otherwise, press Download and let Rufus do the heavy lifting.
  5. Patience. The latest edition of Windows 10 is knocking on the door of 6 GB, and if your connection is slow, waiting is key. Once the download is complete, Rufus will attempt to dump the contents of the Windows 10 image onto the USB drive. The program needs to erase everything on that drive, but you should receive a warning first. Confirm the operation and wait until it finishes.
The Windows 10 download menu on the left, and the warning before erasing the USB drive on the right.

How to "format Windows 10"

Great! You have the Windows 10 installation USB drive ready. Next is to boot the computer from that drive... and here we need your help. Unfortunately, manufacturers haven't agreed on a standard, so the option may be called "Boot Menu", "Boot Order", "Change Boot Order", "Change Boot Priority" or something similar, and I've seen keyboard shortcuts like F2, F3, F8, F10, F11, F12, and other combinations. With a little extra attention at the start, you can identify the correct combination, and when you enter the menu, select the USB drive from the list. If all goes well, you'll arrive at the Windows 10 installation phase.

An example of a Boot Menu or Boot Manager. The USB drive here is simply called "USB Device", but it may carry the manufacturer's name.
You should arrive at a screen like this.

The Windows 10 installer starts with basic questions like language and time format. Then you click Install Now, enter the product key (if you don't have it, click "I don't have a product key"), choose the Windows 10 edition to install, accept the terms, and choose "Custom" as the installation type. The next phase is when you manage partitions, and here we must pause to share two messages:

  1. The process is destructive. If you still have data to back up or want to use other recovery methods, stop now.
  2. Once again: The process is destructive. If you still have data to back up or want to use other recovery methods, stop now.
The existing partitions on the drive. You need to delete all of that...

In our example, the SSD has four partitions that were automatically generated by the previous Windows 10 installation. Your goal is to select each one and click Delete until it says "unallocated space". Leave that drive with unallocated space selected, and click Next. Windows 10 will create new partitions, format them (i.e., "format"), and proceed to install. The rest is a matter of following each step until Windows 10 is installed, but the main mission is accomplished.

When you click Next, the installer will create new partitions and give them the correct format for use.

"I can't delete anything, what do I do?"

I understand perfectly, but I have to be honest here: If you can't delete anything, it's because you don't have backups, and if you don't have backups... start with that before "format Windows 10". A viable alternative is to learn how to restore Windows 10, choosing the "Keep my files" option. Windows 10 will do its best to remove settings and applications while preserving personal files. Is it perfect? No, but you'll have to work with that if a data purge isn't an option.

If formatting Windows 10 isn't an option, try resetting the computer while keeping your files.

There's also the shortcut of recovery images or partitions preinstalled on systems like laptops. In an emergency, the user can follow that procedure to restore the computer to its original factory state, although it usually doesn't preserve personal files. There's no generic guide for this, and you'll need to consult the official documentation if you think that's a better option.

In summary

"Format Windows 10", or rather, reinstalling Windows 10 is a fundamentally tedious, frustrating process with many unknowns for those who haven't done it before. I admit the text shared here isn't as exhaustive as I'd like, but it offers a solid foundation to know exactly what you'll face, from creating the installation USB drive to removing previous partitions. Be patient, take it easy, don't delete anything you can't afford to delete, and as always: Backups, backups, backups. Good luck!