4. Checking for a valid partition
If the BIOS can see the drive but the drive isn’t working, make sure the drive is partitioned. Use FDISK, a command-line utility you’ll find on a Windows 9x/Me startup disk, to check. Boot from the write-protected startup disk and type FDISK. When asked whether or not you want large disk support, type Y.
If the active partition’s type is FAT, FAT32, or NTFS, it should be recognized by the operating system. One exception would be if you put an NTFS drive into a Windows 9x/Me system. The OS wouldn’t recognize the NTFS because it doesn’t support NTFS, not because it was partitioned incorrectly.
If it is a partition problem, you have two choices: Try to recover the data using a disk recovery program, or give up on the data, delete the partition, and re-create it in FDISK. If you want to try recovery first, see the section below on Advanced Data Recovery Options.
If you want to delete the partition and re-create it, return to the FDISK main screen by pressing [Esc] and deleting the partition (option 3 on the screen), and then return to the main screen again and create a partition (option 1 on the screen). After using FDISK to create or delete partitions, you must reboot the machine before doing anything else.
5. Checking drive formatting
If FDISK recognizes the drive and it has a valid partition type, you should be able to view the drive’s content from a command prompt via your startup disk, or from the Recovery Console in Windows 2000 or XP. Change to that drive by typing its drive letter followed by a colon and pressing [Enter]. Then, display a list of files on the drive with the DIR command.
If you see a message about an invalid media type, the drive is probably not formatted using a file system that your OS recognizes. You can either try a data recovery program, or you can give up on the drive’s data and reformat it with the FORMAT command.
6. Fixing physical and logical drive errors
Let’s assume at this point that your OS finds the drive and can read some files on it, but not all of them. Maybe you’re receiving read or write errors, or certain programs aren’t working right. The problem is likely a physical or logical disk error.
A physical disk error is a bad spot on the drive. It can result from physical trauma to the computer, like knocking it off of a table while it’s running.
A logical disk error is a discrepancy between the two copies of the file allocation table (FAT) on the disk, or a discrepancy between the FAT’s version of what clusters are stored on the drive and the reality of actual storage. Such errors are typically caused by improperly shutting down the PC or abnormal program termination.
A message about a data error while reading or writing the drive is probably a physical error. Logical errors are manifested in many different ways, not always directly attributable to the disk itself. For example, certain programs might fail to run or might lock up after starting. Such a problem could mean a memory parity error or even a bad cooling fan; you never know until you check the system and eliminate the possibilities.
It’s best to try the simplest solution first, so run a disk-checking program. Windows 9x/Me/2000 comes with ScanDisk, which will check for both physical and logical errors. Windows XP comes with a similar utility called Check Disk. In Windows XP, access Check Disk from the Tools tab of the drive’s Properties sheet. In early versions of DOS, a command-line utility called CHKDSK does the same thing. Use it with the /F switch to fix any errors it finds.
7. Checking and reactivating disks in the Windows 2000/XP OSs
Windows 2000 and Windows XP both have a Disk Management feature that checks the status of each drive on your system. This utility allows you to convert to dynamic disks, change space allocation, and much more.
With Disk Management, the most important thing to check is the status of each drive. The Windows Disk Management application will display the drive's status. If a drive reports that it is offline or a status other than Healthy, right-click it and choose Reactivate Disk.
Because so much is stored on hard disks, knowing how to revive a failed hard drive is a critical function for technology professionals. Having an effective guide to the recovery process might mean the difference between a total loss and full recovery. With this seven-step process, though, you’ll be ready to tackle most hard disk errors that arise.
This article first appeared in TechRepublic's TechProGuild section.