Bootsect 是 Vista win7 系统安装盘里带的一个小工具，位于 boot 文件夹下。它的主要作用是更新硬盘分区的主启动代码，以在 BOOTMGR 和 NTLDR 之间切换。另外还可以使用此工具还原计算机上的启动扇区。次工具会替换 FixFAT 和 FixNTFS Bootsect 命令行选项
Bootsect 使用下列约定：
bootsect.exe {/help | /nt52 | /nt60} {SYS | ALL | <DriveLetter:>}[/force]
如： win7和xp引导是不同的，如果用 c:ootootsect.exe（空格）/nt60（空格）c: ，则使用win7启动；
而 c:ootootsect.exe /nt52 c: ，就是切换到xp启动了；
例如，如果要将与 NTLDR 兼容的主启动代码应用到标记为 C 的卷，可以使用如下命令：
C:BOOT>BOOTSECT.EXE /NT52 C: Target volumes will be updated with NTLDR compatible bootcode.
C: (\?Volume{7bef1dca-fd61-11dd-844f-806d6172696f})
Updated NTFS filesystem bootcode. The update may be unreliable since the volume could not be locked during the update:
Bootcode was successfully updated on all targeted volumes. Reference: Bootsect 命令行选项 bootsect.exe使用介绍
C:BOOTDDDD>BOOTSECT.EXE /help
bootsect {/help|/nt60|/nt52} {SYS|ALL|<DriveLetter>:} [/force] [/mbr]
Boot sector restoration tool
Bootsect.exe updates the master boot code for hard disk partitions in order to switch between BOOTMGR and NTLDR. You can use this tool to restore the boot sector on your computer.
/help Displays these usage instructions.
/nt52 Applies the master boot code that is compatible with NTLDR to SYS, ALL, or <DriveLetter>. The operating system installed on SYS, ALL, or <DriveLetter> must be older than Windows Vista.
/nt60 Applies the master boot code that is compatible with BOOTMGR to SYS, ALL, or <DriveLetter>. The operating system installed on SYS, ALL, or <DriveLetter> must be Windows Vista or Windows Server 2008.
SYS Updates the master boot code on the system partition used to boot Windows.
ALL Updates the master boot code on all partitions. ALL does not necessarily update the boot code for each volume. Instead, this option updates the boot code on volumes that could be used as Windows boot volumes, which excludes any dynamic volumes that are not connected with an underlying disk partition. This restriction is present because boot code must be located at the beginning of a disk partition.
<DriveLetter> Updates the master boot code on the volume associated with this drive letter. Boot code will not be updated if either 1) <DriveLetter> is not associated with a volume or 2) <DriveLetter> is associated with a volume not connected to an underlying disk partition.
/force Forcibly dismounts the volume(s) during the boot code update. You should use this option with caution.
If Bootsect.exe cannot gain exclusive volume access then the file system may overwrite the boot code before the next reboot. Bootsect.exe always attempts to lock and dismount the volume before each update. When /force is specified, a forced dismount is attempted if the initial lock attempt fails. A lock can fail, for example, if files on the target volume are currently opened by other programs.
When successful, a forced dismount allows exclusive volume access and a reliable boot code update even though the initial lock failed. At the same time, a forced dismount invalidates all open handles to files on the target volume. This could result in unexpected behavior from the programs that opened these files. Therefore, you should use this option with caution.
/mbr Updates the Master Boot Record without changing the partition table on sector 0 of the disk that contains the partition specified by SYS, ALL, or drive letter. When used with /nt52 option, the master boot record is compatible with operating systems older than Windows Vista. When used with the /nt60 option, the master boot record is compatible with Windows Vista or Windows Server 2008.
Example:
To apply the master boot code that is compatible with NTLDR to the volume labeled E:, use the following command:
bootsect /nt52 E: