What is Master Boot Record (MBR)

Definition: A master boot record is a kind of boot sector stored on a hard disk drive or other storage device. The master boot record on a hard drive contains the necessary computer code to start the boot process.
A master boot record consists of three major pieces: the master partition table, the disk signature, and the master boot code.
The master boot record is created when a hard drive is partitioned but is not located within a partition. The master boot record is located on the first sector of a disk. The specific address on the disk is Cylinder: 0, Head: 0, Sector: 1.
In Windows 7 and Windows Vista, you can repair a corrupted master boot record using the bootrec command from System Recovery Options.
In Windows XP, the master boot record can be repaired using the fixmbr command. See How To Repair the Master Boot Record in Windows XP for help.
A volume boot record is another type of boot sector.

Also Known As: MBR, master boot sector, "sector zero"

Examples:

"The new antivirus program I started using scans my PC during the boot process for viruses that attack the master boot record. I once had a virus destroy mine and the computer wouldn't start at all after that!"

How To Enter Windows XP Recovery Console

Boot From the Windows XP CD:-

Windows XP Recovery Console - Step 1 of 6

To enter Recovery Console in Windows XP, you will need to boot from the Windows XP CD.

1. Watch for a Press any key to boot from CD... message similar to the one shown above.
   
2. Press a key to force the computer to boot from the Windows CD. If you do not press a key, your PC will continue to boot to the Windows XP installation that's currently installed on your hard drive. If this happens, just restart and try to boot to the Windows XP CD again.

Allow Windows XP to Begin the Setup Process:-

Windows XP Recovery Console - Step 2 of 6

No user intervention is required in this step. Windows XP is loading a number of files in preparation for either a reinstallation of Windows XP or for use of the Recovery Console.
Note: Do not press a function key if asked to do so during this process. Those options are only necessary when installing Windows XP or reinstalling Windows XP and only then in certain circumstances.

Press R to Enter Recovery Console:-

Windows XP Recovery Console - Step 3 of 6

When the Windows XP Professional/Home Setup screen appears, press R to enter Recovery Console.

Choose the Windows Installation:-

Windows XP Recovery Console - Step 4 of 6

The Recovery Console is now loading but needs to know which Windows installation to access. Most users only have a single Windows XP installation so the choice is usually clear.
To the Which Windows installation would you like to log onto question, press 1 and then Enter.

Enter the Administrator Password :-

Windows XP Recovery Console - Step 5 of 6

The Recovery Console now needs to know the administrator password for this Windows XP installation. Unless you are using a PC in a sizable business network, the administrator password is most likely the same password you use to access Windows XP on a daily basis.
Still not sure what the administrator password is? Offline NT Password & Registry Editor, a free program typically used to reset lost Windows passwords, also has the ability to transform standard user accounts into administrator accounts, all without needing access to a working Windows installation!
To the Type the Administrator password request, enter the password and press Enter.
Note: If you do not have a password or Windows XP normally starts without asking for one, simply press Enter.

Make Necessary Changes in Windows XP Recovery Console:-

Windows XP Recovery Console - Step 6 of 6

The Recovery Console is now fully loaded and the cursor should be sitting at the prompt, ready for a command, as shown in the screen shot above.
Make any changes necessary in the Windows XP Recovery Console. When complete, take out the Windows XP CD and type exit to restart the computer.

Note: A limited number of commands are available for use from within Recovery Console. See the complete list of Recovery Console commands for more information.