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How to Fix MBR Without Windows 7/8/10 Installation CD, DVD or USB Disk

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    After a virus attack, I can’t enter Windows 7 any more, and it seems that MBR has been damaged. Now, I’m eager to know how to fix MBR without Windows 7 DVD or CD disc (I just got the PC with Windows 7 preinstalled, so I don’t have an installation disc). Is there a tool to help me complete this operation?

    Indeed, if MBR (master boot record) is damaged, Windows will be unbootable since this boot code will perform the following actions:
    • Scans the partition table for the active partition.
    • Finds the starting sector of the active partition.
    • Loads a copy of the boot sector from the active partition into memory.
    • Transfers control to the executable code in the boot sector.

    Tip: here MBR refers to the master boot code, not including partition table and disk signature.

    Well, how can we repair the damaged MBR in Windows 7/8/10?

    If you have a Windows installation disk, such as CD, DVD, and USB flash drive, fix MBR by doing these operations: choose "Repair your computer" or similar feature and run "Startup Repair". Or execute bootrec /fixmbr, bootrec /fixboot, and bootrec /rebuildbcd commands in Command Prompt.

    But what if there is no Windows installation disk? Keep reading to get specific steps.

    How to Fix MBR Without Windows 7/8/10 Installation Disk

    To do this, you need to use bootable partition manager. It is a kind of tool that can boot computer and perform partitioning operations like fix MBR without loading Windows OS.

    MiniTool Partition Wizard Bootable Edition is highly recommended since it is free, easy to use, and brings no damage to data.

    Firstly, please download MiniTool Partition Wizard Bootable CD (an iso file), and burn it to CD, DVD, or USB disk.

    Then, start computer from Partition Wizard Boot Disk.

    Tip: remember to set the boot disk as the first boot device in BIOS.

    Next, select the disk where Windows is installed and click "Rebuild MBR" feature from the left action pane.

    fix MBR select system disk

    After these operations, a pending operation will emerge on the left:

    fix MBR apply change

    At this time, just click "Apply" to start fixing MBR, which just takes a few seconds. After the application is completed, please shut down the program, take out bootable disk, and boot computer from local disk. Then, Windows should be bootable again.

    Now, all of you would know how to fix MBR without Windows 7.8/10 installation CD, DVD, or USB disk. For video help, please see Rebuild MBR.