Advices

Advices on “do-it-yourself” diagnosis

To give you solid recommendations over phone or via e-mail, we need to know the mode of your device. On an HDD, it is usually written on a label placed on the top cover after the word MODEL.

For example, the label shows:
HITACHI Deskstar — this is not a model, it is a trademark, see below:
MODEL: HDS722580VLSA80 — this is the disk model.

Knowing the model, we would immediately find that this is Hitachi Deskstar, 7,200 rpm of 80 GB capacity. Many drive models has their own specific problems, and that makes it easier for us to understand what went wrong.

All faults can be divided into logical, electronical, and mechanical. They have different symptoms. The table below helps you to understand what has happened.

Fault types

1. HDD not rotate

PC power On?
No
BAD controller
Yes
There are extraneous sounds
at startup? »»
No
Electrical problem
Yes
Mechanical problem

2. HDD rotate

Heads knock-knock »»
Yes
Heads bad
No
HDD recalibrate? »»
No
Firmware is BAD
Yes
HDD detected in BIOS
No
Firmware is BAD
Yes
HDD reading by logic
No
Firmware is BAD
Yes
SMART Ok?
No
Bad blocks
Yes
Logic infringements



These are the symptoms of the logical faults with possible causes in brief:

While computer's startup, BIOS recognizes all devices, but OS does not start
  • The computer tries to start from a device without system files. For example, an empty diskette is in the FDD drive, or a non-bootable disc is in the CD drive, and there is no alternative startup devices specified in BIOS.
  • The system files are corrupted or deleted in the root folder, the other data being available. Connect the disk to other computer with an operational OS, and copy the files. Do not try to re-install the OS or use any program that would change data on the disk (Partition Magic, NDD, fdisk, format and the likes) until you copy all necessary files to another storage device.
    NEVER allow checkdsk or other similar programs automatically start when the disk is connected to another computer!!! When Windows XP or 2000 is starting up, they will automatically start after the request to check disks if your do not press any key in 10 sec. ALWAYS stay close and watch the startup procedure until it finishes.
  • The system disk is re-formatted. When connected to an operational system it can be read but it is empty. Data can be recovered by using special utilities.
    NEVER use utilities that modify data on the original disk: that cannot be undone!!! Later on, that will make data recovery much more difficult or even impossible!!! Never save recovered data on the disk where they resided!!! You MUST NOT use Undelete or NDD!!!
  • Boot sectors of the file systems are corrupted. That may be a result of power failures, system faults, virus attacks, or incorrect OS setup. (for example, BigLba support is not turned on in the Windows Registry for disks large than 128 GB). Data can be recovered by using special utilities.
  • PQ Partition Magic (or similar utilities) faults or failures while manipulating with partitions (changing their sizes, transferring, changing their file system types, etc.).
  • Surface defects in system sectors (partition tables, boot records, file allocation tables, root folders, etc.).
OS starts but some folders and/or files are inaccessible
  • The content of a folder is damaged, that is, it is impossible to interpret it. That may happen when a file is accidentally written incorrectly, and cross-linked cluster chains appear. That may result in the fact that the content of such file may overwrite either another file or a folder.
  • The content of the folder can be read but incompletely. That may happen when one folder's sector cannot be read (a surface defect), or appears an empty record interpreted as a message that this folder contains nothing more, or a correct FAT chain is absent for a large folder with many records.
  • Also a situation is possible when a user does not have the access rights to this folder (for the NTFS file system). This situation is typical when an old user profile becomes inaccessible when the OS has been re-installed.
  • The content of the folder may be deleted accidentally or intentionally.
Some files cannot be opened
  • An application closed this file incorrectly, and its content is partially damaged.
  • Data has been recovered from a partially damaged partition to the same partition.