ARCHIVED: In Windows 95, 98, or Me, how can I repair the Master Boot Record on my hard drive?

Warning: If you are not completely comfortable with the following procedure, do not attempt it. Any mistakes you make can lead to the loss of data or cause your computer to malfunction. Do not use the fdisk utility to repair your Master Boot Record if you are using any of the following:

• Windows XP
• Windows NT
• Windows 2000
• Unix
• Linux
• Third-party boot partition programs (e.g., System Commander, PartitionMagic)
• Multiboot systems that require you to choose the operating system during the boot-up process

Entering fdisk /mbr may erase important boot sector information, render your hard disk unusable, and result in the loss of data. Contact the manufacturer's support personnel to determine the problem and the correct solution.

Repairing the Master Boot Record

Damage to the Master Boot Record can occur because of virus activity, problems installing software, or errors during system installation. Some symptoms of a problem are:

• When you boot your PC, you get a message stating that setup was not completed for a program.
• Your computer hangs. It does not produce the DOS prompt or an opening screen.

If you are running DOS 5.0 or later, Windows 95, Windows 98, or Windows Me, you can use the fdisk utility to try to repair the Master Boot Record. When you use fdisk with the mbr parameter, the Master Boot Record is rewritten to the hard disk without altering the partition table information on the disk. To run this utility, follow these steps:

1. Boot your PC with a bootable floppy that has the fdisk program on it. See the Knowledge Base document ARCHIVED: In Windows 95, 98, or Me, how do I make a startup (system recovery) disk?
2. At the DOS prompt, enter:

     fdisk /mbr

   This activates the hard drive for a short time. A new DOS prompt will appear.
3. Remove the floppy and reboot.

This information was adapted from article 69013 in the Microsoft knowledge base.