A clean install of Windows 11 means building a bootable USB drive with Microsoft's Media Creation Tool, starting the PC from it, and installing Windows onto a wiped drive. The tool is a free download from Microsoft, you need a blank USB drive of at least 8 GB, and the whole job is mostly waiting once the drive is ready. The step that matters most happens before you start: backing up everything you want to keep, because a clean install removes it.
Who this is for and what you will have at the end
This guide is for anyone who needs to reinstall Windows 11 on a PC that is slow, infected, corrupted, or being handed to a new owner, and for anyone setting up a used or newly built PC with no operating system. It assumes you can reach a working Windows PC, which can be a different computer from the one you are fixing, to build the USB drive.
At the end you will have a freshly installed copy of Windows 11 from Microsoft's own installer, an activation status you have checked, and your boot order set back to normal. You will also know when a clean install is the wrong tool. Microsoft's recovery guidance treats installation media as a last resort for when nothing else works or you suspect malware, so read the next section before you wipe anything.
Decide whether you need a clean install
Windows 11 has several ways to repair or reinstall, and a USB clean install is the most disruptive. Microsoft's Recovery options page describes them like this:
| Option | Where | What happens to your data |
|---|---|---|
| Reinstall Windows (via Windows Update) | Recovery options | Keeps files, apps and settings; the least disruptive reinstall |
| Reset this PC, keep my files | Settings, or WinRE under Troubleshoot | Keeps personal files; removes apps and settings |
| Reset this PC, remove everything | Settings, or WinRE under Troubleshoot | Removes personal files, apps and settings |
| Cloud rebuild | Settings > System > Recovery > Rebuild PC, or WinRE under Troubleshoot > Cloud rebuild | Fresh Windows and drivers from Windows Update; removes personal files, apps and settings. Windows 11 only |
| Clean installation | Boot from installation media | Removes Windows, personal files, apps and settings from the selected drive |
If the PC still starts, try the gentler options first. EpiFive's guide to resetting this PC in Windows 11 while keeping files covers that route. Use USB media when Windows will not start at all, when a reset fails, when you suspect malware, or when the drive is blank.
Also check the manufacturer's website before using Microsoft's generic media. Microsoft notes that OEM recovery images usually include hardware-specific drivers and factory apps that generic installation media may lack. On a business laptop that can mean a Wi-Fi or touchpad driver you have to hunt for after setup.
Prerequisites
Microsoft's Download Windows 11 page lists what you need to create the media:
- An internet connection. Provider fees may apply, and download time depends on your speed.
- A blank USB flash drive of at least 8 GB. Any content on the drive is deleted. (A blank DVD of 8 GB or more and a burner also work.)
- Enough free space on the computer or drive that will hold the ISO file, if you choose to save an ISO.
- A target PC with a 64-bit processor. Microsoft states that Windows 11 can only run on 64-bit CPUs, and that the PC should meet the Windows 11 device specifications. Installing on unsupported hardware may cause compatibility issues.
- Administrator rights on the PC where you run the tool.
- The installation language must match your current language, so choose the same one during setup.
The Media Creation Tool supports x64 processors only. If your PC runs on an Arm processor, this tool is not the right route; Microsoft lists Arm64 ISOs separately on the same download page.
If you are not sure the PC qualifies, run through the Windows 11 hardware requirements check for TPM, Secure Boot and CPU support first. If it fails, Windows 11 unsupported hardware alternatives explains your options.
Before you wipe: back up and check activation
Back up your files
Microsoft's installation media page tells you to back up your files before installing or reinstalling Windows. Copy documents, photos, browser bookmarks, mail archives and anything stored in folders such as Desktop or Downloads to an external drive or to cloud storage. Files that already sync to OneDrive or another cloud service are not affected by a cloud rebuild, but confirm the sync is complete rather than assuming it. Open the cloud service's website and check that the newest files are there.
Do not store the backup on the same physical drive you are about to wipe, and do not use the installer USB drive, because creating the media erases it.
Make a list of the apps you need to reinstall, and note any license keys for paid software. A clean install removes apps and settings.
Check activation first
Microsoft's activation page explains the two ways Windows 11 is licensed. A digital license, which Windows 11 calls a digital entitlement, activates Windows without a key and is tied to your hardware and your Microsoft account. A product key is a 25-character code, typical for PCs sold with Windows preinstalled, boxed copies and volume licenses.
To see which applies, go to Start > Settings > System > Activation. Microsoft advises confirming that Windows is activated and that your Microsoft account is linked to the license before you reinstall. With a digital license you can reinstall the same edition without entering a product key, and you sign in with the linked Microsoft account afterward so activation completes automatically.
If you use a product key instead, locate it before wiping. Microsoft also says many devices have the key embedded in firmware, and that it applies automatically if it matches the Windows version and edition you install.
Create the Windows 11 USB installer
Do this on a working Windows PC with the blank USB drive plugged in.
- Open a browser and go to Microsoft's Download Windows 11 page:
https://www.microsoft.com/software-download/windows11. - Find the section "Create Windows 11 Installation Media" and select Download Now. This downloads
MediaCreationTool.exe. - Run the file as an administrator and accept the license terms.
- On the "What do you want to do?" page, choose the option to create installation media for another PC, then select Next.
- Select the language, edition and architecture. Choose the 64-bit option, and keep the language the same as the one currently on the PC you are reinstalling.
- Choose USB flash drive and select Next, then pick the correct drive from the list. Check the drive letter carefully, because the drive will be erased.
- Wait while the tool downloads Windows 11 and writes it to the drive. When it reports the drive is ready, select Finish.
If you would rather keep an image, the same tool can save an ISO file instead. An ISO is also what you use for a virtual machine, since no USB drive is needed there. Microsoft's download page separately offers an x64 multi-edition ISO that uses your product key to unlock the correct edition.
Stay on official sources
Only download the tool from microsoft.com. Search results and ads often point to look-alike sites offering cracked ISOs or tools bundled with unwanted software. The only file name you need is MediaCreationTool.exe from Microsoft's own page. If a site asks you to pay for the download or to disable your antivirus, close it.
Boot the target PC from the USB drive
- Plug the USB drive into the PC you want to reinstall and turn it on or restart it.
- If the PC does not start from the drive on its own, open the boot menu. Microsoft lists the common keys as F2, F12, Delete or Esc, but the key varies by manufacturer and shows briefly on the first screen. Alternatively, change the boot order in the BIOS or UEFI settings.
- Select the USB drive. If it does not appear, Microsoft notes you may need to temporarily disable Secure Boot in firmware settings.
When setup loads, you will see the Install Windows page.
Run the installation
On the Install Windows page, confirm your language, time and keyboard settings, and select Install Windows. Setup then walks you through its screens. Two points need care:
- Product key. If you are asked for a key and the PC previously had that edition activated, Microsoft says you can select I don't have a product key, which also lets you skip the prompt when reinstalling a previously activated edition. On a new device or motherboard, the same option lets you finish setup, sign in with a Microsoft account and buy a digital license from the Store afterward.
- Choosing the drive. For a clean install you pick the drive that holds the old Windows and let setup remove it. Read the drive list carefully. If the PC has a second internal drive holding backups, do not select it.
The PC restarts several times. Leave the USB drive in until setup tells you to remove it or the first normal start-up screen appears.
After setup: restore normal booting and check activation
Revert the boot order
Microsoft warns that after installation you should undo any boot order changes so the internal drive boots normally. Otherwise the Install Windows page may appear again after installation. If you only used the one-time boot menu, nothing needs reverting, but unplug the USB drive anyway.
If you disabled Secure Boot to boot the drive, turn it back on in the firmware settings after setup.
Confirm activation
Open Start > Settings > System > Activation. If you had a digital license and signed in with the linked Microsoft account, Windows should show as activated. If you use a product key, select Change product key and enter it.
If activation fails after hardware changes such as a motherboard replacement, Microsoft says to link your Microsoft account to the digital license beforehand so you can use the Activation troubleshooter. If an OEM replaced the motherboard, the PC should usually reactivate on its own.
Install updates and drivers
Run Windows Update until it reports nothing pending. Then check the manufacturer's support page for any drivers Windows Update did not supply, such as graphics or touchpad drivers. Reinstall your apps and restore your files from the backup.
Troubleshooting
| Problem | What to try |
|---|---|
| The PC ignores the USB drive | Open the boot menu (F2, F12, Delete or Esc, depending on the maker) or change the boot order in BIOS/UEFI. |
| The drive does not appear as a boot option | Temporarily disable Secure Boot, as Microsoft suggests, then re-enable it after setup. |
| The Install Windows page appears again after setup | The boot order still puts the USB drive first. Remove the drive and fix the boot order. |
| Setup does not match your language | Microsoft states the installation language must match your current language. Rebuild the media in the matching language. |
| Windows is not activated | Check Start > Settings > System > Activation, sign in with the Microsoft account linked to the license, or use Change product key. See Microsoft's Windows activation errors article for specific codes. |
| Wi-Fi or touchpad does not work | Check the manufacturer's support page for drivers; consider OEM recovery media next time. |
Closing checklist
- Decide a clean install is needed; try Reset this PC or a cloud rebuild if Windows still starts.
- Back up files to a separate drive and verify they open.
- Note your activation status and any product key.
- Download the Media Creation Tool only from Microsoft's Download Windows 11 page.
- Use a blank USB drive of at least 8 GB and build the installer.
- Boot from the drive, run Install Windows and pick the right drive.
- Remove the USB drive, fix the boot order and re-enable Secure Boot.
- Confirm activation, run Windows Update, and restore your files.
References
- Microsoft, Download Windows 11: https://www.microsoft.com/software-download/windows11
- Microsoft Support, Create installation media for Windows: https://support.microsoft.com/en-us/windows/create-installation-media-for-windows-99a58364-8c02-206f-aa6f-40c3b507420d
- Microsoft Support, Recovery options in Windows: https://support.microsoft.com/en-us/windows/recovery-options-in-windows-31ce2444-7de3-818c-d626-e3b5a3024da5
- Microsoft Support, Activate Windows: https://support.microsoft.com/en-us/windows/activate-windows-c39005d4-95ee-b91e-b399-2820fda32227
- Pages checked 2026-11-02.
This guide was researched and drafted with AI assistance and checked against the vendor documentation listed in its References. Read the maintained version and related guides on EpiFive.
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