Windows installation starts with a bootable USB drive and a product key

Installing Windows on a new PC means creating a bootable USB drive from a Windows installation file, plugging it into your computer, and walking through the setup screens. You will need a Windows product key (a 25-character code) to set up Windows after installation. If you do not have a key yet, you can purchase one from Microsoft or a retailer, or you can install Windows in trial mode and add the key later. The entire process takes 20 to 45 minutes depending on your drive speed and internet connection.

Before you start, back up any files on the PC if it already has a working operating system — the installation will erase the drive you choose. If this is a brand-new PC with no operating system, you have nothing to back up and can proceed directly to creating the bootable drive.

Key Takeaways

  • You need a Windows installation file (downloaded from Microsoft), a USB drive with at least 8 GB of space, and a product key to set up Windows after setup.
  • Use the Media Creation Tool from Microsoft to turn a blank USB drive into a bootable Windows installer.
  • Boot from the USB drive by restarting your PC and pressing the boot menu key (usually F12, Del, or Esc) during startup.
  • During setup, choose the drive where you want Windows installed, and Windows will format it and copy files automatically.
  • After installation finishes, enter your product key during the set up step, or skip it and add the key within 30 days.

read the Windows installation file and Media Creation Tool

Go to the Microsoft Windows read page and select the version you want — Windows 11 Home, Windows 11 Pro, or Windows 10 (if your PC is older or you prefer it). Click the read button for the Media Creation Tool, which is a small program that prepares your USB drive. Save it to your computer and open it.

The Media Creation Tool will ask whether you want to upgrade an existing Windows installation or create installation media. Choose "Create installation media for another PC." It will then ask you to select the language, edition, and architecture (64-bit or 32-bit — choose 64-bit unless you have a specific reason not to). On the next screen, select "USB flash drive" as your media type.

Plug in a blank USB drive with at least 8 GB of space. The tool will list it and ask you to confirm. Click next, and the tool will read the Windows files and write them to the USB drive. This step takes 10 to 20 minutes depending on your internet speed. Do not unplug the drive until the tool says it is finished.

Insert the USB drive and restart your PC

Once the Media Creation Tool finishes, eject the USB drive safely and plug it into the PC where you want to install Windows. Restart the computer. As it powers on, watch the screen for a message like "Press F12 to enter boot menu" or "Press Del for setup." The key varies by manufacturer — common ones are F12, F2, Del, Esc, and F10. Press it repeatedly as the PC starts up.

The boot menu will show a list of devices. Find the USB drive (it may be labeled with the drive brand or say "USB Device") and select it. Your PC will boot from the USB drive and load the Windows setup screen. If you do not see a boot menu, restart again and try a different key. If that does not work, restart once more and look for a message that tells you which key to press — it usually appears for only a few seconds.

Walk through the Windows setup screens

The setup wizard will ask you to choose your language, time zone, and keyboard layout. Select your preferences and click next. On the next screen, click "Install now." You will then see a screen asking for your product key. If you have one, enter it. If you do not have a key yet, click "I do not have a product key" — you can add it later within 30 days, and Windows will still install and run.

Read the license terms and check the box to accept them. Click next. On the "Which type of installation do you want?" screen, choose "Custom: Install Windows only (advanced)." This option lets you select which drive to install Windows on and gives you control over partitioning.

Select the drive and let Windows format it

The next screen shows all the drives in your PC. If this is a new PC with one empty drive, you will see one entry. Click on it to select it, then click next. Windows will ask you to confirm that you want to format the drive — this erases everything on it. Click OK. Windows will then copy files to the drive and install itself. This step takes 10 to 20 minutes. Your PC may restart several times during this process — let it happen and do not unplug anything.

If you see multiple drives listed and you are not sure which one to choose, look at the size. Your main drive is usually the largest one. If you are still unsure, unplug any external drives before restarting, so only your internal drive shows up. You can plug external drives back in after Windows is installed.

Complete setup and enter your product key

After the files finish copying, your PC will restart and ask you to set up Windows. You will choose a region, keyboard layout, and network. Windows will ask whether you want to set up for personal use or work use — choose based on how you plan to use the PC. You will then create a user account with a password.

When setup asks about set up, enter your product key if you have one. If you skipped the key during installation, you can enter it now. If you do not have a key, click "I will do this later." Windows will run in trial mode for 30 days, during which you can use all features. After 30 days, you must enter a key or Windows will show a watermark and limit some settings. You can purchase a key from Microsoft or a retailer at any time and add it through Settings > System > set up.

Troubleshooting common installation problems

If your PC does not boot from the USB drive, the drive may not be bootable. Restart your PC, go back to the Media Creation Tool on another computer, and create the drive again using a different USB drive. Make sure the drive is completely blank before you start — the tool will format it, but some very old drives may have issues.

If setup stops or shows an error during the file copy, the USB drive may be faulty or the connection may be loose. Try unplugging the drive and plugging it back in, or try a different USB port. If the error persists, create a new bootable drive on a different USB drive. If setup fails after you have already installed Windows, restart in Safe Mode by holding Shift while clicking Restart in the power menu, then try to repair Windows through Settings > System > Recovery > Reset this PC.

If you see a message saying "Windows cannot be installed to this disk," the drive may be using a partition style that Windows does not recognize. This is rare on new PCs but can happen on older ones. You will need to wipe the drive and convert it to the correct format using a tool like Diskpart — this is an advanced step, and you should search for instructions specific to your situation before attempting it.

Frequently Asked Questions

Can I install Windows without a product key?

Yes. You can skip the key during setup and install Windows in trial mode. It will run fully for 30 days, then show a watermark and prevent you from changing some settings. You can add a key at any time within 30 days and set up Windows when ready. After 30 days, you must have a valid key to continue using Windows normally.

What if I lose my product key?

If you purchased Windows from Microsoft, check your email for a receipt with the key. If you bought it from a retailer, check your receipt or account on their website. If you upgraded from an older version of Windows, the key may be stored in your Microsoft account — sign in at account.microsoft.com and look for your product keys. If you cannot find it, you will need to purchase a new key.

Do I need internet during installation?

No. Windows will install without internet. However, you will need internet after installation to read drivers for your hardware (especially graphics card and network drivers) and to set up your product key. If your PC does not have built-in Wi-Fi, plug in an ethernet cable after installation, or use another computer to read drivers and transfer them on a USB drive.

Can I install Windows on an external drive?

Technically yes, but it is not recommended. Windows runs much slower on an external drive, and some features may not work. If you need a portable Windows installation, use a virtual machine instead — run Windows inside software like VirtualBox on another computer. For a new PC, install Windows on the internal drive.

What is the difference between Windows 11 Home and Pro?

Home is for personal use and includes all core features. Pro adds tools for business, like Group Policy, Remote Desktop, and BitLocker encryption. For a new personal PC, Home is sufficient. Choose Pro only if you need those specific business features or plan to use the PC in a corporate environment.