Got a Damaged Master Boot Record?

Although those messages sound pretty scary, there's a good chance your hard drive is still intact. In most cases this problem can be fixed with a simple procedure that repairs your Master Boot Record (MBR). When you start your computer, the BIOS (basic input/output system) looks for the MBR on the first sector of your hard drive. The MBR tells the BIOS which partition on the hard drive contains the operating system.

So... if the MBR is damaged, the BIOS can't locate and start the operating system. When your BIOS detects a damaged MBR or boot sector, you'll see ominous messages like Invalid partition table, Error loading operating system, or Missing operating system. In some cases, dark clouds will apppear on the horizon, and you may hear the distant rumble of thunder. But fortunately, the Recovery Console offers some tools to help clear up the problem.

Repairing a Damaged MBR

Your Windows XP setup CDROM has a tool called the Recovery Console, which is designed to help you repair a damaged master boot record or boot sector. To start the Recovery Console and fix your damaged MBR, follow these steps:

1. Restart your computer with the Windows XP Setup disk in the CDROM drive.
2. If you are prompted to press a key to start the computer from CDROM, do so quickly. Otherwise it may try to boot from the hard drive.
3. After a few minutes, you'll see a prompt to press the R key to start the Recovery Console.
4. When Recovery Console starts, it will prompt you to enter a number corresponding to the Windows XP installation that you need to repair. In most cases, you'll enter "1" (which will be the only choice). If you press ENTER without typing a number, Recovery Console will quit and restart your computer.
5. Enter your Administrator password. If you don't enter the correct password, you cannot continue.
6. At the Recovery Console command prompt, type fixmbr and then verify that you want to proceed.

Your damaged MBR will be replaced with a shiny new one, and you should then be able to boot your system normally. In some cases, you may need to repair the boot sector in addition to the MBR. If your system still doesn't boot properly, repeat the steps above, but issue the fixboot command instead.

NOTE: These procedures assume that you have only one operating system installed. If you are an advanced user and have a multi-boot system with more than one operating system, you may need to do some additional reading about the fixmbr and fixboot commands at the Microsoft website.

Do you have experience with a damaged master boot record? Post your comments below...