Microsoft Windows XP, Microsoft Windows XP OEM Upgrade
Repairs the master boot record of the boot disk. The fixmbr command is only available when you are using the Recovery Console.
The following example writes a new master boot record to the device specified:
If you do not specify a device_name, a new master boot record will be written to the boot device, which is the drive on which your primary system is loaded.
If an invalid or nonstandard partition table signature is detected, you will be prompted whether you want to continue. If you are not having problems accessing your drives, you should not continue. Writing a new master boot record to your system partition could damage your partition tables and cause your partitions to become inaccessible.
Information in this document was provided by the manufacturer.