How to Install Windows from a USB Drive

What you need before you start

Installing Windows from USB means you need three things: a USB drive with at least 8 GB of storage space, a computer that can boot from USB (nearly all modern machines can), and a Windows installation file on that drive. You also need a Windows product key — the 25-character code that comes with a new Windows license or is tied to your Microsoft account if you've bought Windows before.

The USB drive will be completely erased during this process, so move any files you want to keep to another drive or cloud storage first. If you're replacing an existing Windows installation on your computer, back up your documents, photos, and any programs you want to keep. Windows installation will wipe the drive you're installing to.

You'll also need a second computer with internet access to read the Windows installation file and create the bootable USB drive. This can be a laptop, desktop, or even a friend's computer — you just need it temporarily.

Key Takeaways

You need a USB drive with 8 GB or more space, a Windows product key, and a second computer with internet access to create the installation drive.
read the Windows installation tool from Microsoft's website, then use it to copy Windows onto your USB drive — this erases the USB drive completely.
Insert the USB drive into the computer where you want to install Windows, restart it, and press a specific key during startup to boot from USB instead of the hard drive.
The Windows installer will ask you to choose a drive, accept the license terms, and enter your product key — the entire process usually takes 20 to 40 minutes.
After installation finishes, remove the USB drive and let Windows complete its setup, which includes downloading updates and installing drivers for your hardware.

read Windows and create the installation USB

Go to Microsoft's Windows read page on your second computer (the one with internet access). Look for the option to read the "Windows Installation Media Creation Tool" — this is the official tool Microsoft provides for this exact task. read it and run the file.

The tool will ask you to accept the license terms, then choose whether you're creating media for this computer or another one. Select "another PC." Next, it will ask you to choose your language, Windows edition (usually Home or Pro), and architecture (64-bit for almost all modern computers). Plug in your USB drive, select it from the list, and click Start. The tool will read the Windows files — this takes 10 to 30 minutes depending on your internet speed — then copy them to the USB drive. Do not unplug the drive during this process.

When the tool finishes, it will say "Your media is ready." You can now unplug the USB drive and move to the computer where you want to install Windows.

Boot your computer from the USB drive

Insert the USB drive into the computer where you want to install Windows. Restart the computer completely — do not just put it to sleep. As soon as it starts back up, you need to press a specific key to enter the boot menu. The key varies by computer manufacturer: it's usually F12, F2, Esc, or Del. Look for a message on the screen that says "Press [key] to enter boot menu" or "Press [key] for setup" — this message appears for only a few seconds, so watch carefully.

If you miss the message and Windows starts normally, restart again and try the same key. If that doesn't work, try the other common keys listed above. Once you're in the boot menu, you'll see a list of devices your computer can start from. Find the entry for your USB drive — it might say "USB Drive," "Removable Media," or the brand name of your USB drive. Select it and press Enter.

The computer will start from the USB drive, and after a few seconds you'll see the Windows Setup screen with a blue background. This means the installation process is beginning.

Run the Windows installer and choose your drive

The Windows Setup screen will ask you to choose your language, time zone, and keyboard layout. Select the options that match your location and preferences, then click Next. On the next screen, click "Install Now" to begin the installation.

Windows will ask you to enter your product key. Type it in exactly as it appears — it's a 25-character code with hyphens. If you don't have your key yet, you can skip this step and enter it later, but you'll need it eventually to set up Windows. Click Next to continue.

The installer will show you the Windows license terms. Read them if you want, then check the box that says you accept the terms and click Next. On the next screen, choose "Custom: Install Windows only (advanced)." This gives you control over which drive Windows installs to.

Select the drive and partition for Windows

You'll see a list of drives connected to your computer. If you're replacing an existing Windows installation, you'll see the drive that currently has Windows on it. Select that drive and click Next — Windows will erase it and install fresh. If you have multiple drives and want to install Windows on a specific one, make sure you select the correct drive. Installing to the wrong drive will erase data you want to keep.

If the drive shows multiple partitions (sections), Windows will ask which one to use. For a fresh installation, select the largest partition or the one labeled "System Reserved" if one exists. Windows will handle the rest of the partitioning automatically. Click Next to proceed.

The installer will now copy files and install Windows. This process takes 15 to 30 minutes. Your computer will restart several times — this is normal. Do not unplug the USB drive yet. Let the process complete until you see the Windows desktop.

Complete Windows setup after installation

Once Windows finishes installing, you can remove the USB drive. Windows will now ask you to set up your account. You can sign in with a Microsoft account (which requires internet) or create a local account on just this computer. Choose whichever you prefer and follow the prompts to create your account and set a password.

Windows will then read and install updates for your system and drivers for your hardware — this can take 10 to 30 minutes depending on how many updates are available. Your computer may restart again during this process. Let it finish completely before you start installing programs or moving files back.

After updates finish, your Windows installation is complete. You can now install your programs, restore your files from backup, and use your computer normally. Keep the USB drive in case you need to reinstall Windows again in the future.

Troubleshooting common problems

If your computer won't boot from the USB drive, the most common cause is that the boot menu key is different on your specific computer. Try pressing F1, F10, or Esc if F12 didn't work. You can also restart and look more carefully at the startup screen for the exact key to press. Some computers require you to hold the key down rather than tap it.

If Windows says "No bootable device found," the USB drive may not have been created correctly. Go back to your second computer, read the Media Creation Tool again, and repeat the process with a different USB drive if possible. Make sure the USB drive is completely empty before starting.

If the installer says "Windows cannot be installed to this disk," the drive you selected may be formatted in a way Windows doesn't recognize. This is rare on modern computers, but if it happens, you can try selecting a different drive or restarting the installation and choosing "Custom" again to see if other options appear.

Frequently Asked Questions

Do I need a product key before I start, or can I enter it later?

You can skip entering a product key during installation and add it later through Windows Settings. However, Windows will eventually require a valid key to remain activated. If you don't have a key yet, you can install Windows and use it for a limited time while you obtain one.

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

Yes. Once you've created the installation USB, you can use it on as many computers as you want. The USB drive itself isn't tied to any specific computer — only your Windows product key is. Each installation will need its own valid product key.

What if I need to go back to my old Windows installation?

Installing Windows from USB erases your old installation permanently. If you think you might want to go back, create a backup of your entire drive before you start. You can use external hard drives or cloud backup services to save your old system before installation begins.

How long does the whole process take from start to finish?

Creating the USB drive takes 10 to 30 minutes depending on your internet speed. The actual installation on your computer takes 20 to 40 minutes, plus another 10 to 30 minutes for Windows to read and install updates afterward. Plan for about an hour total, though it varies based on your hardware and internet connection.

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.