The Fdisk MBR switch is an undocumented switch that can be used with DOS fdisk to replace or repair the MBR file. This can be done if the MBR file becomes corrupted or infected. WARNING if you have a multi-boot drive you could end up loosing access to one or all of your operating systems. It would be a good idea to backup the MBR or drive before you run Fdisk /MBR. I use to have a lab where the computer and students all got infected with the NYB virus which attaches itself to the MBR files and then infects any drive that reads or writes files from the hard drive. To correct the problem and get rid of the virus we would boot the computers from a clean DOS floppy or CD and run fdisk /mbr and this would correct the problem. Once the student floppies or flash drives got infected the virus would migrate rapidly throughout the lab. I wasn’t until we put on a good anti-virus program that we were able to clean and rid ourselves of the problem. The fdisk mbr switch has helped in the past but good anti-virus software is a better long term fix.
FIXMBR
The FIXMBR website has some additional articles you might find useful.
The MBR (master boot record) file is on the first sector, 512 bytes, of your hard drive. This file contains the hard drive partition table, boot start-up program, and a drive signature. The file resides outside the hard drive partitions on the first sector of the drive and can be repaired using fdisk mbr in DOS or fixmbr command using the Windows recovery console. It would be a good idea to backup the MBR before any changes or modifications are made. There are many MBR utilities that can be found at CNET download for backing up, editing, or making changes to the MBR. The boot start-up or sometimes referred to as the bootstrap program is used to start the operating system, which is a small machine code program that BIOS uses to start-up the operating system. The last part of the MBR files is a 32 bit drive signature that uniquely identifies the hard drive. Since the MBR file is the first file read before the operating system is loaded it has become the target of a number of viruses. Once the MBR file is infected the viruses will copy themselves into memory and control the operating system. Viruses will normally disable in virus protection and infect any files copies to another other device.
To better understand how the Fdisk program operates or the Recovery Console you can find those posts here at this site under the Categories.
FIXMBR
The FIXMBR website has some additional articles you might find useful.
The Fdisk is a DOS command available when you boot your computer to DOS and type in fdisk at the command prompt. Using fdisk you can partition a hard drive and set active the boot partition. You are limited to only one primary partition using the DOS fdisk command and four partitions. This is because DOS will destroy itself if it sees more than one primary partition. Microsoft therefore limited fdisk to creating only one primary partition. However you can create an extended partition and within the extended partition create multiple logical drives. I have created some more resources for running the fdisk command and creating partitions. You can view some additional Fdisk resources at the following sites: Fdisk YouTube video and Fdisk article document.
Another good utility for partitioning a hard drive is GParted a free Open Source utility that runs on Linux. I like to run GParted from a Live CD Linux distribution using Insert. This allows me to have complete control over the computer by running my operating system from just the CDROM and allowing me access to the hard drive. You could also use Insert to recover files on a non functioning hard drive. Insert then becomes a valuable recovery tool and maintenance tool. For more information concerning GParted I have a GParted HuPage that you can view.
FIXMBR
The FIXMBR website has some additional articles you might find useful.
The Recovery Console can be used to boot your computer and recover files and fix several computer related problems. There are many commands that can be accessed in Recovery Console, including the ability to start or stop services, some admin tasks, format hard drives, and read and edit NTFS file system files.
You can start Recovery Console by rebooting your computer to the Windows setup install CD. You will need to set your BIOS so that the computer will first boot from the CDROM.
Once started you will need to select the operating system and use your administrator password to logon.
Once logged on you can use the help command to view all the different commands available. Some of these commands are del (delete file), copy (copy file), md (make directory, rd (remove directory), attrib (change the attributes of a file), chkdsk (checks hard disk and provide a report), dir (displays files in a directory), and exit (exits the Recovery Console and restarts your computer)
The command FIXMBR can be used to correct or repair the MBR (master boot record) file. The MBR file is in the first sector of the hard drive and contains partition information needed for the operating system to boot and recognize the different partitions and logical drives available.
The Recovery Console can be very useful for repairing files and recovering or correcting a non functioning operating system or faulty hard drive.
FIXMBR
The FIXMBR website has some additional articles you might find useful.
The FIXMBR is one of several Windows Recovery Console commands. After you select the operating system and logon
you can type FIXMBR at the prompt and the MBR (master boot record) is rebuilt and replaced with a new MBR file. This can usually correct some of the startup problems with a corrupted or infected MBR record. Since the MBR record is the first 512 bytes read on the boot hard drive it is also a target for many viruses. If the MBR gets infected the virus can move into memory and control all other boot processes and disable any anti-virus programs. Most anti-virus programs like AVG will detect and stop viruses, but if you boot the computer to an infect device, such as, a floppy or CD, it can infect the MBR. Just rebooting the computer to Recovery Console and using FIXMBR will remove the virus and correct the problem. One WARNING that should be mentioned is that dual boot systems where you have more than one bootable operating system on a hard drive can be affected so that you lose the ability to boot the alternate operating system. You might want to backup the MBR record first just so you can restore it if needed. I also have a FIXMBR YouTube video you might find helpful.
FIXMBR
The FIXMBR website has some additional articles you might find useful.
