This is the most direct method and doesn't require downloading extra software if you have a Windows installation or recovery USB.
bootrec /rebuildbcd — Scans for installations and rebuilds the Boot Configuration Data. How Do I Fix the Master Boot Record (MBR)?
: Insert your Windows installation USB/DVD and boot from it. Hard Drive Mbr Repair Software
bootrec /fixmbr — Writes a new Windows-compatible MBR to the system partition.
bootrec /fixboot — Writes a new boot sector to the partition. This is the most direct method and doesn't
: Type these commands in order, pressing Enter after each:
: Select Repair your computer > Troubleshoot > Advanced options > Command Prompt . : Insert your Windows installation USB/DVD and boot from it
If your computer refuses to boot or displays errors like "Operating System not found," a damaged Master Boot Record (MBR) is often the culprit. You can fix this using built-in Windows tools or dedicated third-party software.