Here is a guide on how to repair a damaged MBR.
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:
- Restart your computer with the Windows XP Setup disk in the CDROM drive.
- 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.
- After a few minutes, you'll see a prompt to press the R key to start the Recovery Console.
- 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.
- Enter your Administrator password. If you don't enter the correct password, you cannot continue.
- 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.
EDIT: Here's the Source: http://askbobrankin.com/fix_mbr.html
Edited by Artellos, 09 March 2008 - 10:40 AM.