How to repair a damaged boot sector by replacing the master boot record (MBR) in Windows XP

Your computer may continually restart, sometimes load the Windows logo screen, or even just have a black screen. There are a number of symptoms that occur when you have a damaged boot sector such as the master boot record.

What is a boot sector of a hard drive?

Your hard drive is split into small sectors and the first of these is the boot sector. It is the most important and is obviously accessed first when the computer first boots up. If your hard drive is not partitioned it will have a Volume Boot Record.

What can damage the Master Boot Record in the Boot Sector?

• Having problems when installing Operating Systems can damaged the master boot record.


• Stopping half way through installation is the most common cause.


• Changing the Windows Registry entries.


• Getting a virus that infects the MBR. Many viruses are built to attack the MBR.

What you will need to Repair the master boot record (MBR) of a hard drive?

1. An original Full Version Windows XP. The one you used to originally put Windows on your computer. An OEM version may not have this option, it depends on the company it came from. ( Dell, Acer, HP, etc)


2. You will need to know the administrator password for your Windows installation.

How to repair the master boot record (MBR of a hard drive manually (quicker).?

1. Put your original Windows XP CD into the cd drive of your computer.


2. Restart your computer and hopefully it will come up and say press any key to boot from the cd.


3. So therefore you must press any key on your keyboard to start from the cd.


4. If this does not come up you need to enter your bios and change the boot order or sequence. How to get into Your BIOS and change settings
   Sooner or later you will have to go into your computers bios and change certain settings. The main reason I go in there is to set the boot sequence or boot order of the computer. Different computer makes and models have different version and types of bios however they all have the common basics, but may call them different things.
   To access any bios on any computer you must watch the startup screen on the computer. It will usually say "To enter setup press......." Some common keys you may have to press are F1, F2, F10, or maybe the delete key. You must press this key when the startup screen is showing. If you miss this you have to restart again.
   Once you have entered the bios there will be a menu to choose from. Some Bios have Boot sequence as a menu item, but if they do not you have to find it under another menu name. Once you have found it, change the cd rom to be the first to boot to, then hard drive as the second. This is for when you format your computer. To change it back, repeat steps and change it to boot to hard drive 0.
5. A blue screen will appear and you are on your way..


6. You may need to press F8 to agree to the Windows Setup agreement.


7. After that the setup options will appear (see screen shot below).


8. Do not press ENTER as it will start installing Windows from scratch and you will loose all of your data on your hard drive.


9. Press the letter R on your keyboard to enter the Recovery Console.


10. When Recovery Console starts you will have to enter the number that corresponds with the installation you want to repair. For example if you have only one Windows installed on your computer then you would press the number one key. If you have two operating systems on your computer and you want to repair the second one then press 2.


11. Enter your Administrator password for that windows installation. You must enter an admin password here and if you do not, you cannot continue.


12. At the Recovery Console command prompt, type fixmbr.


13. You will be asked to confirm that you want to do this by pressing the Y key for yes.


14. Now your Master Boot record will be fixed.

Now if that did not work you can also repair the Boot sector by following the same steps but typing fixboot instead of fixmbr.