Install or Format Windows Without a USB Pendrive

Want to reinstall or format Windows but don’t have a USB drive or DVD? Don’t worry — you can still install Windows using only your internal hard drive.

In this guide, I’ll show you a reliable method to create a virtual Windows installer inside your PC and boot into Windows Setup just like a normal USB installation. No pendrive, no external media, and no risky third-party tricks. Everything is done using official Windows files and a trusted boot configuration tool.

This method is beginner-friendly, works for both Windows 10 and Windows 11, and is especially useful if you’re stuck without a USB drive but still need a clean Windows installation.

Let’s get started.

Files You Need Before We Start

Before we begin the actual process, you need to download two files. These are safe, official, and required for creating the virtual installer.

First, we need EasyBCD, a boot configuration tool that lets us add a custom Windows Setup option to the boot menu.

Next, download the Windows ISO file directly from Microsoft. You can choose either Windows 10 or Windows 11 depending on what you want to install.

Once both downloads are complete, keep them ready. In the next step, we’ll create a small partition that will act like a virtual bootable USB drive.

Step 1: Create a 10GB Virtual Installer Partition

Now we’re going to create a small partition inside your hard drive. This partition will behave like a bootable USB drive and store the Windows installation files.

Don’t worry — this does not delete your data. We’re only shrinking free space.

1. Right-click the Start button
2. Select Disk Management

You’ll see all your drives and partitions listed.

3. Find the drive that has the most free space
   (Usually this is Drive C:)
4. Right-click the drive → choose Shrink Volume

Windows will calculate how much space can be reduced.

5. In the size box, enter:

10240 MB

That equals exactly 10GB.

6. Click Shrink

You’ll now see 10GB Unallocated space.

7. Right-click the unallocated space
8. Select New Simple Volume
9. Click Next through all steps and finish using default settings

After this, a new drive letter will appear in File Explorer. This is your virtual installer partition.

In the next step, we’ll copy Windows setup files into this partition.

Step 2: Copy Windows Installation Files to the Partition

Now we’ll move the Windows setup files into the new 10GB partition so it behaves like a real bootable installer.

1. Locate the Windows ISO file you downloaded earlier
2. Right-click the ISO → click Mount

Windows will open it like a DVD drive. You’ll see a new drive appear in File Explorer.

3. Open that mounted drive
4. Press Ctrl + A to select all files
5. Right-click → Copy
6. Open the 10GB partition you created
7. Paste all the files there

This may take a few minutes depending on your drive speed.

Once copying finishes:

8. Go back to the mounted ISO drive
9. Right-click → Eject

Now your 10GB partition contains the full Windows installer, exactly like a bootable USB.

In the next step, we’ll use EasyBCD to add this installer to your boot menu.

Step 3: Install and Configure EasyBCD

Now we’ll use EasyBCD to tell your computer that the 10GB partition contains a Windows installer and should appear in the boot menu.

1. Open the EasyBCD installer you downloaded earlier
2. Install it normally like any other program
3. After installation, launch EasyBCD

If it asks about commercial vs personal use:

• Choose Non-commercial / Home use

If you see a message like “Bootloader detected”, just click OK.

Now inside EasyBCD:

4. Click Add New Entry
5. Go to the WinPE tab
6. Set the type to WIM Image (RAM Disk)
7. Click Browse
8. Open your 10GB partition
9. Go to the folder:

sources

10. Select the file:

boot.wim

11. Give the entry a name like:

Windows Installation

12. Click the + (Add Entry) button

EasyBCD will now create a new boot option.

Next, we’ll make sure the boot menu always appears when your PC starts.

Step 4: Enable the Boot Menu at Startup

Now we’ll configure the boot menu so you can choose between your normal Windows and the installer when the PC starts.

1. In EasyBCD, go to Edit Boot Menu
2. You should see two entries:
   • Your current Windows
   • Windows Installation
3. Select the option:
   Wait for user selection

This makes the boot menu appear every time the computer starts instead of auto-booting.

4. Click Save Settings

That’s it — the virtual installer is now fully configured.

Next, we’ll restart the PC and boot directly into Windows Setup.

Step 5: Boot Into Windows Setup

Now it’s time to use the virtual installer we created.

1. Restart your computer
2. During startup, a boot menu will appear
3. Select:

Windows Installation

Your system will now load the Windows Setup environment — exactly the same screen you see when installing from a USB drive.

This may take a little longer than a normal boot. That’s normal.

Once Windows Setup appears:

4. Choose your language and keyboard layout
5. Click Install Now

In the next step, we’ll complete the Windows installation safely.

Step 6: Install or Format Windows

You are now inside the official Windows Setup screen. From here, the process is exactly the same as installing Windows from a USB drive.

1. Click Install Now
2. If asked for a product key:
   • Enter your key, or
   • Click I don’t have a product key (Windows will activate later if your PC has a digital license)
3. Choose your Windows edition (if prompted)
4. Select:

Custom: Install Windows only (Advanced)

You’ll now see a list of partitions.

👉 If you want a clean format:

• Select your old Windows partition (usually the largest primary partition)
• Click Format
• Then click Next

⚠️ Be very careful not to format the wrong partition or you will lose your data.

Windows will now start installing. Your PC will restart several times — this is normal.

In the next step, I’ll show you what to select after the restart so you don’t accidentally loop back into setup.

Step 7: Select the Correct Windows After Restart

During installation, your PC will restart automatically one or more times.

When the boot menu appears again, you will still see:

• Your old Windows
• Windows Installation

👉 This time, do NOT select Windows Installation again.

Instead, choose your newly installing Windows (the normal Windows option).

If you select the installer again, the setup will restart from the beginning and you’ll get stuck in a loop.

After choosing the correct option, Windows will continue installing and move to the first-time setup screen.

In the next step, we’ll finish the final Windows setup and clean up the installer partition.

Step 8: Finish Windows Setup

After installation completes, Windows will boot into the first-time setup screen.

Here you’ll just follow the normal setup steps:

1. Select your region
2. Choose your keyboard layout
3. Connect to Wi-Fi or Ethernet
4. Sign in with a Microsoft account (or create a local account)
5. Choose privacy settings

Windows will automatically install basic drivers and prepare the desktop. This may take a few minutes.

Once finished, you’ll land on the Windows desktop and your system will be fully ready to use.

Next, we’ll clean up or hide the installer partition so it doesn’t appear in File Explorer.

Step 9: Hide or Remove the Installer Partition (Optional)

Now that Windows is fully installed, the 10GB installer partition is no longer needed. You can either hide it or delete it to recover space.

Option 1 — Hide the partition (safer)

This keeps the files but removes it from File Explorer.

1. Right-click Start → open Disk Management
2. Right-click the 10GB partition
3. Choose Change Drive Letter and Paths
4. Click Remove

The partition will still exist, but it won’t appear in Explorer.

Option 2 — Delete and merge space back

Only do this if you’re sure installation is complete.

1. In Disk Management, right-click the 10GB partition
2. Click Delete Volume
3. You’ll see unallocated space
4. Right-click your main drive (usually C:)
5. Choose Extend Volume

This gives the space back to your main drive.

That’s it! You’ve successfully installed Windows without a USB pendrive. 🎉