Fixmbr is a Recovery Console command that writes a new master boot record to the hard disk drive that you specify.
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.
In the above example, the master boot record is written to the drive located at DeviceHardDisk0.
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.
The fixmbr command is only available from within the Recovery Console in Windows 2000 and Windows XP.