Her er lidt oplysninger om hvad fdisk /mbr gør og lidt andet om mbr, hvis det har interesse.
Hos M$ knowledgebase:
The MS-DOS Fdisk utility usually updates the master boot record (MBR) only if no master boot record exists. Repartitioning with Fdisk does not rewrite this information.
Fdisk has an undocumented parameter called /mbr that causes it to write the master boot record to the hard disk without altering the partition table information.
What is the MBR?
At the end of the ROM BIOS bootstrap routine, the BIOS reads and executes the first physical sector of the first floppy or hard disk on the system. This first sector of the hard disk is called the master boot record (or sometimes the partition table or master boot block). There is a small program at the beginning of this sector of the hard disk. The partition information, or partition table, is stored at the end of this sector. This program uses the partition information to determine which partition is bootable (usually the first primary DOS partition) and attempts to boot from it.
This program is written to the disk by the fdisk /mbr command and is usually called the master boot record. During typical operation, Fdisk writes this program to the disk only if there is no master boot record.
NOTE: The fdisk /mbr command only re-writes the MBR on the system drive (DISK-0) using BIOS calls. You cannot specify any other drive for the fdisk /mbr command to operate on other than DISK-0.
Der kan læses mere her:
http://www.ata-atapi.com/hiwmbr.htmog her:
http://www.geocities.com/thestarman3/asm/mbr/MBR_in_detail.htm