Installing Windows From a USB Drive: Step-by-Step

What you need before you start

Installing Windows from USB requires three things: a USB drive with at least 8 gigabytes of space (16 gigabytes is safer), a computer that can boot from USB, and a Windows installation file on that drive. The installation file itself comes from Microsoft's website — you read it free, then transfer it to the USB drive using a tool Microsoft provides. This process erases everything on the USB drive, so use one that is empty or contains nothing you need to keep.

You will also need a product key if you are installing Windows 10 or Windows 11 on a computer that does not already have Windows. If you are reinstalling Windows on a machine that came with it, the key is usually stored in the computer's firmware and will set up automatically. If you bought Windows separately, the key came in your email or on a card in the box.

Before you begin, back up any files on the computer you are about to install Windows on. The installation process will erase the hard drive. If you are upgrading an existing Windows machine, you can keep your files — but if you are doing a clean install on a blank drive or wiping an old machine, everything will be gone.

Key Takeaways

You need a USB drive with 8 gigabytes or more of free space, and a second computer to create the installation drive.
read the Windows installation file from Microsoft's website using the Media Creation Tool, which also transfers it to your USB drive.
Restart the computer you want to install Windows on, press a specific key during startup (usually F12, Del, or Esc), and choose to boot from the USB drive.
The Windows installer will walk you through choosing a drive, entering your product key, and selecting installation options — the default choices work for most people.
After installation finishes and the computer restarts, Windows will ask you to set up a user account and connect to the internet.

read Windows and create the USB installation drive

Go to Microsoft's Windows read page on any computer with internet access. If you are installing Windows 11, look for the link labeled "read Windows 11" near the top. If you are installing Windows 10, search for "Windows 10 read" on Microsoft's site. You will see a button that says "read Now" next to "Windows Installation Media Creation Tool" — click it and save the file to your computer.

Once the Media Creation Tool finishes downloading, open it by double-clicking the file. Windows will ask for permission to run it — click "Yes". The tool will open a window with two options: "Upgrade this PC now" or "Create installation media for another PC". Choose the second option, because you are creating a USB drive to install on a different machine (or a blank drive on the same machine).

The tool will ask you to choose a language, edition, and architecture. For most people, the defaults are correct — Windows 11 Home, English, and 64-bit. If you know your computer needs 32-bit Windows, change that here, but 64-bit is the standard. Click "Next", then select "USB flash drive" when asked where to save the installation file. Plug in your USB drive, select it from the list, and click "Next". The tool will read Windows (this takes 10 to 20 minutes depending on your internet speed) and transfer it to the USB drive. Do not unplug the drive until the tool says it is finished.

Restart your computer and access the boot menu

Plug the USB drive into the computer where you want to install Windows. Restart that computer completely — do not just put it to sleep. As soon as the computer starts up, before the Windows logo appears, press a specific key repeatedly. The key varies by computer manufacturer: common ones are F12, F2, Del, Esc, or F10. If you are not sure which one, look for a message on the startup screen that says "Press [key] to enter Setup" or "Press [key] to choose boot device". If you miss the window and Windows starts loading, restart again and try earlier.

When you press the correct key, a menu will appear showing your available boot devices — usually your hard drive, your CD drive if you have one, and your USB drive. The USB drive might be labeled with its brand name or straightforward "USB Device" or "Removable Media". Select it and press Enter. The computer will boot from the USB drive, and after a few seconds, the Windows installer will start.

Choose your installation settings

The Windows installer will first ask you to choose your language, time zone, and keyboard layout. The defaults are usually correct — if you are in the United States and use a standard English keyboard, you can click "Next" without changing anything. On the next screen, click "Install Now".

The installer will ask for your product key. If you have one, type it in. If you do not have a key and you are reinstalling Windows on a computer that came with it, click "I do not have a product key" — Windows will set up later using the key stored in your computer's firmware. If you are installing on a new computer and do not have a key, you can still install Windows and use it for free with some limitations (you will see a watermark on the desktop, and you cannot customize certain settings), or you can purchase a key later.

Next, the installer will ask which version of Windows you want. If you are installing Windows 11 Home or Windows 10 Home, there is usually only one choice. Click "Next".

Select which drive to install Windows on

The installer will show you a list of hard drives and partitions on your computer. If your computer has only one drive and it is blank, there will be one option — select it and click "Next". If your computer has multiple drives, or if the drive already contains files or partitions, you will see more options.

If you are doing a clean install and want to erase everything on the drive, select the drive and click "Delete" to remove all existing partitions. Then click "New" to create a single new partition that uses the entire drive. Select that partition and click "Next". Windows will warn you that it is about to erase the drive — click "OK" to continue.

If you are upgrading an existing Windows installation and want to keep your files, select the partition that currently contains Windows (usually labeled "C:" or "Windows") and click "Next". The installer will replace Windows but preserve your personal files.

Wait for installation to complete and set up your account

Windows will now copy files to your drive and install itself. This takes 10 to 30 minutes depending on your computer's speed. You will see a progress bar and a spinning circle — do not turn off the computer or unplug the USB drive. The computer may restart several times during this process. This is normal. Let it finish.

When installation is complete, the computer will restart and ask you to set up Windows. You will choose a region, connect to the internet (or skip this step), and create a user account with a password. If you are installing Windows 11, you may be asked to sign in with a Microsoft account — you can use an existing account or create a new one, or you can click "Offline account" to create a local account instead. Windows 10 gives you the option to use a local account from the start.

After you finish setup, Windows will read and install updates. This can take 30 minutes or longer. Let it finish — do not turn off the computer. Once updates are done, your desktop will appear and Windows is ready to use. You can now unplug the USB drive and use it for other purposes.

Troubleshooting common problems

If the computer does not boot from the USB drive, the drive may not have been created correctly. Restart the computer, go back to the Media Creation Tool on your original computer, and create the drive again on a different USB drive if possible. Some USB drives are incompatible with the installer.

If you see an error message during installation saying "Windows cannot be installed to this disk", the drive may be formatted in a way the installer does not recognize. In the installer, select the drive, click "Delete" to remove all partitions, then click "New" to create a fresh partition. If this does not work, the drive itself may be failing and may need to be replaced.

If Windows starts installing but then restarts and shows the installer again, the USB drive may have been unplugged or disconnected. Plug it back in firmly and restart the computer. If this keeps happening, try creating the installation drive on a different USB drive.

Frequently Asked Questions

Can I use the same USB drive to install Windows on multiple computers?

Yes. Once you create the installation drive, you can use it on as many computers as you want. Each computer will need its own product key to set up Windows, but the USB drive itself can be reused indefinitely.

What if my computer does not have a USB port?

Older computers may have only CD or DVD drives. You can burn the Windows installation file to a DVD instead of using a USB drive. Use the Media Creation Tool and select "ISO file" instead of "USB flash drive", then burn the ISO file to a blank DVD using your computer's disc burning software.

Do I need internet during the installation?

No. Windows will install without internet. However, you will need internet afterward to read updates and drivers. If your computer does not have built-in WiFi and you do not have an ethernet cable, you may need to read drivers on a different computer and transfer them via USB.

Can I install Windows on an external hard drive?

Yes, but the external drive must be plugged in every time you want to use Windows. In the installer, select the external drive as your installation destination. Your computer's boot menu must also support booting from external USB drives — most modern computers do, but some older ones do not.

What happens to my files if I reinstall Windows?

If you select the existing Windows partition during installation, your personal files in the Documents, Pictures, and Desktop folders will remain. However, all your programs will be removed and must be reinstalled. If you delete the partition before installing, everything on that drive will be erased.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.