written by: Steve McFarlane•edited by: Bill Fulks•updated: 5/31/2010
How to troubleshoot and repair a hard drive that has become unbootable.
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A hard drive may become unbootable if the system files become corrupt or are missing.In some cases the files can be easily copied back to the hard drive, and in other cases there may be issues with the hard drive configuration in the BIOS. In this article we look at some easy ways to resolve this problem.
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When a computer starts, it searches for boot instructions in the BIOS (basic input output system) called the boot sequence. The boot sequence tells it the order in which it should search for an operation system and further boot instructions from installed drives.If it comes upon corrupted boot instructions it may fail to continue the boot process even though nothing is wrong with the primary hard drive on which the OS (operating system) is installed.
An example of this could be a faulty floppy or USB drive that is inserted in the computer while the computer is set to take boot instructions from those sources. To resolve this problem do one of the following:
Remove the offending media.
Enter the BIOS and change the boot sequence to make the primary hard drive first in the boot sequence. This will make the boot process go by a little quicker, but attempts, to boot or do an installation from the CD drive won’t work until the setting is reversed.
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Copying System Files to Make Bootable
Critical system files must also reside in the root directory of the C: drive to enable Windows to boot; the Recovery Console can be used to copy these files back to the root directory if the files are missing. The files include:
Especially if the partition was not formatted using Windows, the FIXBOOT command may need to be used to make the active partition bootable; it too can be run from the Recovery Console.
On older FAT32 operating systems users could copy system files quickly by using the Sys C: /s command.This command copies the system files back to the target disk (in this case the C drive) but it only works if the drive is already formatted.Actually this was best used to make floppy disks bootable to DOS and therefore provided limited functionality to all but those who knew how to navigate the DOS command prompt.
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Primary and Active Partitions
The computer may fail to boot from a partition if it isn’t made active or set as the primary partition. Setting a partition, as the active partition will usually result in Windows viewing it as drive C:, from which it will seek boot instructions by default. Use a disk utility, such as Fdisk, to manually change a partition to ‘active'.
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Reinstall the Operating System
Assuming that the hard drive is correctly installed and is working properly, if none of the above solutions work, then reinstalling the OS may be the only option. This may be the case if the OS installation was severely corrupted and can’t be manually fixed in a timely manner. To reinstall the operating system, following the instructions on the reinstallation CD to complete the process.
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As can be seen from this article, there are quite a few reasons why a hard drive may be unbootable. To repair the hard drive, the system files my need to be reinstalled, the boot sequence and active partitions may need to be changed, or if all else fails, a complete reinstall of the OS may need to be done.