The partition boot sector is a small section of the hard disk partition that contains information about the operating system’s file system (NTFS or FAT32), as well as a very small machine language program that is crucial in assisting the operating system as it loads.
If you suspect that Windows won’t boot because the partition boot sector has been corrupted, you can use a special Recovery Console tool called Fixboot to fix it.
Start by accessing the Recovery Console.
To use the Fixboot tool, from the Recovery Console command prompt, type
Where [drive] is the letter of the drive to which you want to write a new partition boot sector.