How to Install Windows From a Flash Drive

You need a working computer, a flash drive with at least 16 GB of space, and the Windows installation file from Microsoft

Installing Windows from a flash drive means copying the Windows installer onto the drive, then booting your computer from that drive instead of from your hard drive. This lets you install Windows on a computer that has no operating system yet, or replace the one it has. You will need a second computer (one that already works) to create the flash drive in the first place.

The process has three parts: downloading the Windows file on a working computer, writing that file to the flash drive, and then booting the computer you want to install Windows on from that flash drive. Each step is straightforward if you follow the order, but skipping ahead or mixing up the steps will leave you with a flash drive that does not work.

Key Takeaways

You must read the Windows installation file from Microsoft's official website on a computer that already has internet and an operating system.
The flash drive must be at least 16 GB and will be completely erased when you write the Windows file to it, so back up anything on it first.
You create the bootable flash drive using the Media Creation Tool (for Windows) or a third-party tool like Balena Etcher (for Mac or Linux), not by dragging files onto the drive.
On the computer where you want to install Windows, you must change the boot order in BIOS or UEFI so it tries the flash drive before the hard drive.
The Windows installation itself will ask you to choose a drive and partition, confirm you understand the data will be erased, and then walk you through language and account setup.

read Windows from Microsoft on a working computer

Go to microsoft.com/software-read/windows on a computer that already has Windows, Mac, or Linux. You will see a page with a button labeled "read now" under "Windows 11 Installation Media" or "Windows 10 Installation Media" depending on which version you want. Click that button.

This downloads the Media Creation Tool, a small program (about 30 MB) that will do the actual work of writing Windows to your flash drive. Do not try to read Windows itself directly — Microsoft makes you use this tool so the file is prepared correctly for installation.

If you are on a Mac or Linux computer, you cannot use the Media Creation Tool. Instead, read the Windows ISO file directly from the same Microsoft page (look for a link that says "read ISO"), then use a tool like Balena Etcher or Rufus to write it to the flash drive. The steps are similar but the tool is different.

Prepare the flash drive and run the Media Creation Tool

Insert a flash drive into your working computer. The drive must have at least 16 GB of free space — Windows 11 needs about 5.5 GB, but the Media Creation Tool needs extra room to work. If the drive has files on it that you want to keep, copy them to another location first, because this process will erase everything on the drive.

Open the Media Creation Tool you just downloaded. It will ask you to accept the license terms, then show you two options: "Upgrade this PC now" or "Create installation media for another PC." Choose "Create installation media for another PC" because you are making a flash drive to use on a different machine.

The tool will ask you to choose the language, edition (Home or Pro), and architecture (64-bit or 32-bit). For most people, 64-bit is correct — it is the standard for computers made in the last ten years. If you are not sure, choose 64-bit. Then select "USB flash drive" as your media type.

The tool will show you a list of USB drives connected to your computer. Select the flash drive you prepared. Click "Next" and the tool will write Windows to the drive. This takes 10 to 20 minutes depending on your computer and the speed of the flash drive. Do not unplug the drive or close the tool while it is working.

Change the boot order on the computer you want to install Windows on

Insert the flash drive into the computer where you want to install Windows. Restart that computer and watch the screen carefully as it starts up. Within the first few seconds, before the Windows logo appears, you will see a message like "Press F2 to enter Setup" or "Press Del to enter BIOS." The key varies by manufacturer — common ones are F2, F10, F12, and Del. Press that key when ready.

You are now in BIOS or UEFI, the firmware that runs before Windows loads. This is where you tell the computer which device to boot from. Look for a menu called "Boot Order," "Boot Sequence," or "Boot Devices." You need to move the USB flash drive to the top of the list so the computer tries it first.

The exact steps depend on your computer's manufacturer, but usually you can use arrow keys to highlight the USB drive, then press Enter or use + and - keys to move it up. Once the USB drive is first in the boot order, save your changes (usually by pressing F10 or selecting "Save and Exit") and the computer will restart.

The computer will boot from the flash drive and start the Windows installer

After you save and exit BIOS, the computer will restart and boot from the flash drive instead of the hard drive. You will see a Windows logo and a message saying "Press any key to boot from CD or DVD" — even though you are using a flash drive, Windows calls it a DVD for historical reasons. Press any key within a few seconds.

The Windows Setup window will open. It will ask you to choose your language, time zone, and keyboard layout. These are just preferences — you can change them later. Click "Next" and then "Install now."

Windows will ask you to enter a product key. If you have one, enter it. If you do not have one yet, you can click "I don't have a product key" and continue — Windows will let you install and run for free, but you will see a watermark on the desktop and some features will be limited until you enter a key later.

Choose which drive to install Windows on and confirm the erasure

Windows will ask you to choose which drive to install on. If the computer has only one hard drive, there will be only one option. If it has multiple drives, make sure you select the correct one — this is your final note to avoid erasing the wrong drive. Click on the drive and then click "Next."

Windows will show you a warning that it is about to erase the drive and install Windows on it. This is the moment to stop if you realize you selected the wrong drive. If you are sure, click "Install" and Windows will begin copying files. This takes 10 to 30 minutes depending on your computer's speed.

The computer will restart several times during installation. Do not unplug the flash drive yet — Windows may need to read from it again. Let the installation finish completely. When it is done, Windows will ask you to create a user account, set a password, and choose privacy settings. After you finish those steps, you will be at the Windows desktop and the installation is complete.

Remove the flash drive and verify Windows is working

Once you are at the Windows desktop, you can unplug the flash drive. Windows is now installed on the computer's hard drive and will boot from there automatically the next time you restart.

Check that Windows is working by opening a web browser, connecting to the internet, and visiting a website. Then go to Settings and check for Windows updates — Windows will read and install any security patches released since the installation file was created. This usually takes 15 to 45 minutes and may require another restart.

After updates are finished, your Windows installation is complete and current. You can keep the flash drive in case you need to install Windows again on another computer, or erase it and use it for other purposes.

Frequently Asked Questions

What if my computer does not show the "Press F2" message when I restart?

Some computers skip this message if they boot too fast. Try restarting and pressing the BIOS key repeatedly as soon as you see the manufacturer's logo. If that does not work, look up your computer model and "BIOS key" online — the manufacturer's support page will tell you which key to press. You may also need to disable "Fast Boot" in Windows settings first if you are replacing an existing Windows installation.

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

Yes. Once you have created the bootable flash drive, you can use it on any computer. You do not need to recreate it each time. Just insert it, boot from it, and run the installer on the new computer.

What if the flash drive does not appear in the boot order menu?

The drive may not be recognized by BIOS. Try a different USB port — some ports are faster or more compatible than others. If it still does not appear, the drive may be too new or too old for that computer's BIOS. Try a different flash drive, or use a USB external hard drive instead. You can write Windows to an external drive the same way you write it to a flash drive.

Do I need a product key before I install Windows?

No. You can install Windows without a product key and enter one later. Windows will run for free with a watermark on the desktop until you add a key. If you are upgrading from an older version of Windows, your key from that version may work on the new installation.

What happens to my files if I install Windows on a computer that already has Windows?

They will be erased. Before you start, back up any files you want to keep to an external drive or cloud storage. Windows Setup will warn you before it erases the drive, but once you click "Install," the data cannot be recovered.

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.