What Is the Fixmbr Command?:
The fixmbr command is a Recovery Console command that writes a new master boot record to the hard disk drive that you specify.
Fixmbr Command Syntax:
fixmbr (device_name)
device_name = This is where you designate the exact drive location that a master boot record will be written to. If no device is specified, the master boot record will be written to the primary boot drive.
Fixmbr Command Examples:
fixmbr \Device\HardDisk0
In the above example, the master boot record is written to the drive located at \Device\HardDisk0.
fixmbr
In this example, the master boot record is written to the device that your primary system is loaded onto. If you have a single installation of Windows installed, which is normally the case, running the fixmbr command in this way is usually the right way to go.
Fixmbr Command Availability:
The fixmbr command is only available from within the Recovery Console in Windows 2000 and Windows XP.

