This is a little compilation of tips and procedures to help with data recovery from a failed / failing hard drive. The information here can be applied to Desktop/Server/Laptop and external hard drives.
All of us have at one time or another been faced with a bad drive. Most often data gets lost on storage media such as hard disk, floppy disk, RAID arrays, CD/DVD and from other electronic storage devices. Data loss occurs either by physical damage or logical damage. In case of physical damage a CD can have scratches on its surface; a hard disk drive read/write head can crash and a tape can just smash up. In case of logical damage the data is not lost rather somehow its addresses on storage media are inaccessible such as formatting and deletion comes under the category of logical damage of data.
After the initial tearing our hair out in frustration is done over with here are a few guidelines on what can be done to try and get your data back.
Primary Steps - So you cant see the files on the drive / computer wont detect the drive...
> First off, if you can see the drive in Windows Explorer, but are getting errors in trying to read the data try running a Disk Check. Right click on the drive, select Properties, Tools, and select Check drive for errors.
> You can also do that by running a chkdsk /f from the command prompt.
If there are any software / mapping errors, this will fix them. Also when you run a complete test, the drive will be scanned for bad sectors and the faulting regions will be marked unusable by the OS.
Secondary Steps - Cant see the drive at all in the OS / drive not detected in the BIOS
> Reboot the computer and enter the BIOS. Varying BIOS'es will name / locate the options differently, but what you want is to find the option that runs a hard disk check. Let it run and perform a low-level scan of the drive and attempt to fix any errors that may be present.
Tertiary steps - I'm not ready to give up on my data
> Download a copy of the manufacturer's drive diagnostic and repair software. These are generally specific to the manufacturer of you hard drive (eg - SeaGate, Western Digital...). Once you know which hard drive you have (read the manufacturer name and model of the drive visually), locate the manufacturer support site on the internet via Google and download their diagnostic software for your drive. This is generally one of the best methods to find out whats wrong and try to fix it.
> Download a copy of a data recovery tool from the internet, I would recommend something on the lines of the Data Recovery software available here : http://www.stellarinfo.com/
or any software you find yourself comfortable with. Running the application will let you know where you stand.
Erm - Great, but my drives making noises like it's a timer ticking down!
This is one of the most damaging and problematic scenarios. You need to ask yourself something - How much is the data worth?
Noise from the drive (usually a clicking sound) means that the spindle has frozen / drive head has hit the surface of the disk. This is usually irrecoverable without professional help which involves a clean room, opening the drive and replacing the heads, only possible at a specialized data recovery center - again not guaranteed to get your data back. If the data is really valuable, this is your only option.
If the data is personal, and you finally decide you CAN do without it, well, what have you got to loose! This trick, though it sounds a bit off, is actually your best option once all other avenues have failed.
First off, get your new drive setup and install your OS and everything onto your system. You are ready to go. In case of a desktop computer, think and plan to reconnect the failed drive as a slave and set the jumpers accordingly. Incase of a laptop drive, get yourself an external USB kit and keep it hooked up to the system without connecting the failed drive.
Now, the fun part, put the failed drive in a plastic bag, wrap it up tight and put it in the freezer for a couple of hours. Sounds strange, well here is the logic - the cold usually causes the spindle to get unstuck and the drive readable again. Poke me all you want, but it works ;)
Once you are happy with the freezing process, pull out the drive from the bag, *quickly* connect it to your system and start it up. You will have about 10 minutes to get the data off the drive, so plan accordingly and get what you really need first. This process, while getting you the data you REALLY need, will usually brick the drive once the drive has heated up again due to condensation and the spindles locking up again. Usually permanently. But that was were you were before you started. Difference is, you just managed to get that really important data off it first ;)
Hope this gives you a start to getting back what you lost and a better idea of the process.