The /ScanOs option scans all disks for installations that are compatible with Windows Vista or Windows 7. In this scenario, the computer starts by using Windows NT Loader (NTLDR) instead of Windows Boot Manager (Bootmgr.exe). An earlier Windows operating system has been installed after Windows Vista or Windows 7 was installed.The boot sector has been replaced with a non-standard Windows Vista or Windows 7 boot sector.Use this option if one of the following conditions is true: The /FixBoot option writes a new boot sector to the system partition by using a boot sector that is compatible with Windows Vista or Windows 7. Use this option when you must resolve MBR corruption issues, or when you have to remove non-standard code from the MBR. This option does not overwrite the existing partition table. The /FixMbr option writes a Windows 7 or Windows Vista-compatible MBR to the system partition. To do this, type the following commands at the Windows RE command prompt: By doing this, you make sure that the BCD is completely rebuilt. If rebuilding the BCD does not resolve the startup issue, you can export and delete the BCD, and then run this option again. Note Use the Bootrec.exe tool to troubleshoot 'Bootmgr Is Missing' issue. Use the option that is appropriate for your situation. The Bootrec.exe tool supports the following options. For more information about how to configure the computer to start from the DVD drive, see the documentation that is included with the computer or contact the computer manufacturer. Note To start the computer from the Windows Vista or Windows 7 DVD, the computer must be configured to start from the DVD drive. In the System Recovery Options dialog box, click Command Prompt.Click the operating system that you want to repair, and then click Next.Select a language, a time, a currency, a keyboard or an input method, and then click Next.

Put the Windows Vista or Windows 7 installation disc in the disc drive, and then start the computer.

To run the Bootrec.exe tool, you must start Windows RE.

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