Install Windows on a New Hard Drive Without USB

You can install Windows on a replacement drive without a DVD or USB if the computer can still start from its existing Windows installation or recovery environment. The practical method is to download Microsoft’s Windows installation files, place them on the new drive, and start Windows Setup from there; this requires access to a working Windows PC and careful handling of your data.

What You’ll Need

A working Windows installation on the computer, or another Windows PC that can prepare the drive.
An internet connection and enough free space to download Windows installation files.
The new drive installed or connected internally. If you prepare it on another PC, you may need a drive enclosure or adapter.
A backup of files you want to keep, plus your Windows edition and activation details if available.
Administrator access. If BitLocker is enabled on the existing system, save its recovery key before changing drives or boot settings.

Step-by-Step

Confirm that this method fits your situation. It works best when Windows still starts from the old drive, or when you can boot into Windows Recovery Environment and reach Command Prompt. A completely blank computer with no bootable drive, recovery partition, network-based deployment, or other boot source cannot install Windows from nowhere: it needs some way to load Setup. If you have another working computer but no way to boot the target computer, creating installation media is usually the straightforward option.
Back up important files and check activation. Copy documents, photos, and other files to separate storage or cloud storage. Do not rely on the new drive as your only backup. In Windows, open Settings > System > Activation and note whether Windows is activated. A digital license often reactivates after reinstalling on the same computer, but significant hardware changes or a different edition can require additional steps. Note whether your installed edition is Home or Pro.
Download the official Windows installation files. While Windows is running, go to Microsoft’s Windows download page and download the Media Creation Tool or the Windows disk image (ISO) for the edition you need. Use Microsoft’s current download instructions; the available route can differ by Windows version and computer. Do not use third-party “preinstalled” images. If downloading an ISO, right-click it in File Explorer and choose Mount. This makes its files available as a virtual DVD without physical media.
Choose how Setup will reach the new drive. If the old Windows installation is still working and the new drive is connected, you can start Setup from the mounted ISO or extracted installation files. If the new drive is being prepared on another PC, connect it as a secondary drive and use that PC to copy the installation files and create a boot entry as described in the next steps. Do not format or erase the old drive until the new installation has started successfully and your backup is checked.
Copy Setup files to the new drive. In File Explorer, open the mounted ISO, select its files and folders, and copy them to a folder on the new drive, such as WinSetup. The destination should be a normal data partition formatted as NTFS. Keep the existing Windows boot files and partitions intact if the PC still depends on them to start. Copying files alone does not make a blank computer bootable; it only prepares the installer for a computer that already has a working boot path.
Start Windows Setup from the existing Windows session. On the computer you are reinstalling, open the copied folder on the new drive and run setup.exe. If you mounted the ISO on the current Windows installation, you can run setup.exe from the mounted drive instead. Approve the administrator prompt, follow the on-screen checks, and select the option to install Windows. If offered, choose whether to keep files only when the installer confirms that this is supported for your current Windows installation. A clean install normally requires restarting and choosing the new drive or its intended Windows partition.
Use Windows Recovery when the old installation will not start. If Windows reaches its recovery menu, select Troubleshoot > Advanced options > Command Prompt. You can locate the drive letters with diskpart, then list volume, and exit; drive letters in recovery may differ from those in normal Windows. Find the copied installer folder and run its setup.exe from Command Prompt. This route is not available on every recovery setup, and some systems will not launch Setup this way. If it fails, use a supported bootable installer or manufacturer recovery method rather than deleting partitions at random.
Select the correct destination and complete installation. Follow Setup’s prompts and identify the new drive by its capacity and partition layout. On the screen that asks where to install Windows, deleting or formatting a partition permanently removes its contents. Only do so after verifying the drive and backup. For a clean installation, select the intended unallocated space or prepared Windows partition and continue. The computer will restart several times; do not interrupt it. After Windows starts, complete setup, connect to the internet, install updates, and check activation in Settings.
Check the result before removing the old drive. Confirm Windows starts from the new drive, your files are present or restored, and essential devices work. If the computer keeps starting the old Windows installation, use the UEFI/BIOS boot menu or firmware settings to choose Windows Boot Manager associated with the new drive. Keep the old drive unchanged until you are confident the replacement works.

Common Mistakes

Assuming copied Setup files make a completely blank PC bootable. The computer still needs an existing boot source or supported recovery path.
Formatting the old drive before confirming the new installation and backup. This can remove the only working Windows environment and your files.
Selecting the wrong disk in Setup. Check capacity and partitions carefully; drive letters and disk order can change.
Installing a different Windows edition from the one covered by the license, or assuming activation is guaranteed after a motherboard change.
Changing UEFI, Secure Boot, or storage-controller settings without noting the original values. These changes can prevent the old system from starting.

Tips

Disconnect extra storage drives during a clean install if you can do so safely. This reduces the chance of choosing the wrong target or placing boot files on another disk.
Keep the new drive connected to the same computer for installation where possible. Moving a prepared system between PCs can introduce boot and hardware issues.
If replacing a drive in a laptop, consult its service instructions before opening it. Power the device off and unplug it; do not force connectors or remove a battery that is not designed to be removed.
Use the same boot mode as the existing installation, usually UEFI on modern PCs. Avoid mixing legacy boot settings with a UEFI installation.

Troubleshooting

Setup will not open: Make sure the ISO is mounted or its contents were fully copied, then run setup.exe from the installation folder as an administrator. Check that the download completed and the drive has enough free space.
The new drive is not listed: Shut down and check its connection and firmware detection. If it appears in firmware but not Setup, a storage-controller driver may be required. Obtain the correct driver from the computer or motherboard manufacturer and load it through Setup; avoid changing controller modes blindly.
The computer will not boot after installation: Open the firmware boot menu and select the new drive’s Windows Boot Manager. Check that the drive is detected and that the boot mode matches how Windows was installed.
Recovery Command Prompt cannot find the files: Run diskpart, then list volume, and exit to identify the correct letter. Check the folder with dir; recovery drive letters are often different.
Activation or edition is wrong: Confirm the installed edition matches the license and connect to the internet. Use Settings > System > Activation to run the available troubleshooter. If activation still fails, consult Microsoft support or the organization that manages the license.

Frequently Asked Questions

Can I install Windows on a totally blank PC without USB or a disc?
No, not by this method. A blank PC needs a way to start the installer, such as USB, DVD, network deployment, or a manufacturer recovery system. A second drive containing files is not automatically bootable.

Can I run Setup from the new drive while Windows is running?
Yes, if the current Windows installation can start and the installer files are accessible. Running setup.exe begins the process, but a clean installation may still require a restart.

Will installing Windows erase my old drive?
Not unless you select, format, or delete its partitions. Still, back up first and verify the destination disk on every Setup screen.

Can I prepare the new drive using another computer?
You can copy Setup files to it, but moving it back does not guarantee that it will boot the installer. The target computer still needs an existing boot or recovery path.

Do I need a product key?
Not always. If the computer has a valid digital license for the edition you reinstall, activation may happen automatically after it connects to the internet. Choose the matching edition and do not assume a license transfers to different hardware.

Is this the same as cloning Windows?
No. Setup installs Windows; cloning copies an existing installation and its partitions. If you want the new drive to look and behave exactly like the old one, use a reputable cloning process and verify the clone before wiping the original.

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

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