How to Fix the MBR in Windows XP and Windows 7 if the Operating System is Unable to load.

What exactly is the MBR?

The MBR (Master boot record) is a boot sector (a portion of your hard drive) that stores information about your hard drive’s partitions and serves as a loader for the operating system you’re using.

When you first install Windows, the Master boot record is created on the first partition you create. It’s your hard drive’s first 512 bytes.

You won’t be able to boot into Windows if the MBR is corrupted.

MBR is used by all Windows versions, including Windows XP, Vista, 7, and 8, and if it is corrupted, you will be unable to boot.

Viruses that attack the MBR and replace it with their code can cause it to malfunction. 

Following Methods can be used to fix the MBR.

The following two approaches can be used to fix a broken MBR in Windows XP/7.

Choose the first option to repair MBR using Command Prompt if you can access Command Prompt in Windows RE mode (using Windows installation media). You can use the second technique if you don’t have a Windows CD.

Method 1: Using the Command Prompt, repair the MBR on Windows XP and Windows 7.

Method 2: Using freeware to repair the MBR on Windows 10

We’ll use approach 1 in this case:

Following methods can be used to fix the MBR.

Your computer may display some of the following errors if the Master boot record is corrupted: –

1: Error loading operating system

Error loading operating system

2: Operating System not found

2: Operating System not found

3: Invalid partition table

3: Invalid partition table

4: No bootable medium found

4: No bootable medium found

5: Reboot and select proper boot device.

Reboot and select proper boot device.

Fix the MBR in Windows XP

The fixmbr command in Windows XP can be used to repair the MBR. To run Recovery Console and the fixmbr tool, you’ll need the original Windows XP installation CD.

Only Windows XP and Windows 2000 support the fixmbr command.

To run fixmbr, follow these steps:

Start by booting from the Windows XP CD.

Press any key to boot from the CD when the notice “Press any key to boot from CD…” appears.

Press R to launch Recovery Console when the Welcome to Setup page opens.


If Windows XP is the only operating system on your hard disc, type 1 and hit Enter in the “Which Windows installation would you like to log onto” prompt.

window xp


Enter the administrator password in the “Type the Administrator password” question and then press Enter.

admistration password

Step3: Type fixmbr then press Enter.



  • Wait for the procedure to complete. Any damage to the master boot record will be repaired using the fixmbr utility software.



  • Remove the Windows XP CD from the drive.Typeexit.
  • To restart your computer, press Enter.
  • If you were unable to boot your computer due to a damaged MBR, follow the steps above to repair it, and Windows XP should now start normally.


If the fixmbr command fails, use the map command to find the correct drive name where the Master boot record has to be repaired:

1)The type map

2) Press Enter;

3) Wait for the map utility’s output:

C: NTFS 1024MB \Device\Harddisk0\Partition1 E: \Device\CdRom0

The output shown above is an example. Your computer’s output may differ, but take note of the drive letter for the item labelled Harddisk0, in this case.

Fix the MBR in Windows 7


  • Start the computer by booting from the Windows 7 installation DVD.
  • Press any key to boot from CD or DVD…” at the “Press any key to boot from CD or DVD…” screen.

mbr in window 7

Step2: Select a language, keyboard layout then Click Next

install window

Step 3: Click Next after selecting the operating system. When choosing an operating system, make sure to tick the box that says “Use recovery tools to help fix problems starting Windows.”

click next

Step4: Select Command Prompt from the System Recovery Options menu.


Step5: After Command Prompt has loaded successfully, type the following commands.

  • bootrec /rebuildbcd PressEnter.
  • bootrec /fixmbr Press Enter.
  • bootrec /fixboot Press Enter

command prompt


Restart your computer after removing the installation DVD from the disc tray.


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