Boot sector viruses and magnetic errors can corrupt the master boot record (MBR),
which is used by the BIOS’s bootstrap program to locate a bootable
drive. A damaged MBR will prevent your system from starting from a
bootable hard disk. To repair a damaged or corrupted MBR, you can use
one of the following options:
• Windows Vista users can use the Command Prompt within WinRE (System Recovery Options) and type the command
bootrec /fixmbr to repair the MBR. To repair the damaged Boot Manager program, the command would be
bootrec /fixboot. For more information on this fix and other related fixes, see the following link:
http://support.microsoft.com/kb/927392.
• Windows XP/2000 users can use the Recovery Console command Fixmbr on an NTFS-based drive. If the drive is FAT based, first use Fixboot, followed by Fixmbr. To rewrite the boot sector on a FAT-based drive, type Fixboot and press Enter. To repair the master boot record with an NTFS-based drive, type Fixmbr and press Enter.
(If you boot from a different drive letter than the default Windows
drive or a different hard disk than normal, you can specify the hard
disk drive letter or drive number with these commands.)
Because damaged MBRs
can be caused by a computer virus, you should test systems with an
up-to-date antivirus program before using either of these commands. If a
boot-sector virus is located by an antivirus program, the program’s own
disk-repair options should be used first. Don’t forget that many BIOS
programs come with the option to scan the boot sector for viruses. If
you have this functionality in
your motherboard’s BIOS, consider using it! If this is unsuccessful,
you can use the appropriate repair tool to attempt to fix the MBR.
Note
If you see a message at startup referring to EZ-BIOS, Dynamic Drive Overlay,
or a similar message, it indicates the drive has been prepared using a
third-party disk utility, such as old versions of DiscWizard, Disk
Manager, MaxBlast, Data Lifeguard Tools, or other vendor-supplied hard
disk setup programs. If a system has an outdated BIOS that cannot manage
the full capacity of the drive, these programs will install a
nonstandard MBR and drivers to manage the drive’s full capacity. If
systems running third-party hard disk management software can’t boot,
use the repair program provided by the software vendor, not Windows’ own
MBR repair programs.
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