Your computer's hard drive is where all of your programs, files, and operating system (s) are stored. It is a fragile component made up of several magnetosensitive plates generally rotating from 7,200 to 15,000 RPM. The data on the platters is read and modified by the read / write head which moves back and forth. The platters are very fragile and any contact with the read / write head is a very bad thing. Know how to identify a damaged hard drive, how to tell if it is repairable, and how to get your files back. This article deals only with computer hard drives and not with devices that use a proprietary component like the Apple iPod.
Steps
Part 1 of 3: test a damaged hard drive

Step 1. Read the Warnings section
Before doing anything with your hard drive, read the Warnings section below.

Step 2. Find the cause of the problem
Consider whether the hard drive is inaccessible due to a mechanical or software issue.

Step 3. Immediately shut down your computer
If the hard drive makes a strange vibrating or clicking noise, shut down your computer immediately. Remove it by opening the side of your system unit (or the hard drive bay if you have a laptop) and use a screwdriver to detach the drive from its retention bracket. Disconnect the cables at the back and place it in a cardboard box or anti-static bag. You can fix this mechanical problem yourself if you feel up to it. Alternatively, search Google for computer repair or data recovery specialists near you. The operation is expensive, but it can be worth it if your files are very important.

Step 4. Fix the problem yourself
If the hard drive seems to be working normally, but shows up as unformatted in your computer's bios or on Windows, you may be able to fix it yourself. If Windows starts, it means that the C partition is intact and that repairing the second partition or the second disk will be easy. If the hard drive where Windows is located appears unformatted in your computer's BIOS, take it out (following the instructions in step 3) and install it in a working Windows computer. It could be a friend's machine or an old Windows 2000 or XP machine that you no longer use after buying a new one.

Step 5. Purchase an external hard drive rack
If you need to connect a laptop hard drive to a desktop computer or vice versa, purchase a rack that converts your PATA, SATA, or SCSI drive interface to USB or FireWire. Either way, you will need to go through this step depending on the age of the computer you are using to repair your hard drive. Old machines do not support newer devices. Check your hard drive or your computer's manual to be sure.

Step 6. Do not format the damaged hard drive
After installing the damaged hard drive to a computer with a working hard drive, do not format it or copy anything to it. You risk losing your data permanently.

Step 7. Recover your data
Even if the essential operating system files are damaged or deleted, the hard drive will be readable on the other computer and you can easily recover your data in Documents etc. Simply open the folders with Windows Explorer and burn the files you want to recover to DVD or CD for reuse later.

Step 8. Reinstall Windows
Return the hard drive to its original computer and reinstall Windows. It will be formatted and all the information it contains will be erased.

Step 9. Return your files to the hard drive
After installing a new, fully functional copy of Windows, you can put your files back in their places and begin the long process of reinstalling programs.

Step 10. Use data recovery software
If the hard drive in question is a data drive or a Windows drive that shows up as unformatted, use data recovery software. One of the best known is TestDisk, a free tool that scans the hard drive and recovers data. Download it from this link then unzip and install the program.

Step 11. Follow the instructions
Follow the instructions in the program or go to this link for more help.

Step 12. Replace your hard drive
If TestDisk has made your hard drive accessible again, put it back in your computer (if you had to install it in another beforehand) and enjoy your recovered files!
Part 2 of 3: test a working hard drive

Step 1. Create an image of the disc
Use Norton Ghost or Acronis True Image to create an image of your entire hard drive. The image will be the same size as all the contents of the device and you will need to save it to an external hard drive or other drive installed on the machine.

Step 2. Remove the drive you want to test
After creating a full image of the disc, take it out of the computer. Be careful not to damage its fragile components.

Step 3. Install the hard drive in another computer
Install the hard drive in a working computer. Make sure it is installed as a secondary device or slave hard drive.

Step 4. Download HDD Sentinel
This program allows you to perform various tests on your hard drive. The test you are going to run is the write and read test, which consists of writing to the disk and then reading the information to find any faults.
Make sure the correct hard drive is selected

Step 5. Partition and format the hard drive
After testing, use a tool like Paragon Hard Disk or Windows default disk manager to format the hard drive and put your files back on it. Restart your computer after formatting.

Step 6. Test the hard drives
The computer with the hard drive to be tested probably still has its own hard drive. Test the execution of a file on both to verify that they are working properly.
- First of all, open a video file on the main hard drive (the one where the operating system is located). Reading should be smooth and error-free.
- Copy the same video to the freshly formatted hard drive. Start reading and look for a possible fault. If the video is choppy or distorted, it means your hard drive has a problem and may corrupt the files it contains.

Step 7. Replace your hard drive
If your hard drive is damaged, replace it with a new model of equal or greater capacity. Use Norton or Acronis to copy the disk image inside. Put it back on your computer and use it as you normally would.
Part 3 of 3: Use Windows diagnostic tools

Step 1. Open Windows Explorer
Open Windows Explorer by pressing ⊞ Win + E keys. You will see a list of hard drives connected to your computer.

Step 2. Right click on the hard drive you want to test
Select Properties in the menu that appears.

Step 3. Click the Tools tab
You will see different options, but only one Check now interests us.

Step 4. Click Check Now
You may need to enter an administrator password if you are not logged in as an administrator.

Step 5. Check all the boxes
Depending on the version of Windows you are using, you will need to enable error repair. On recent versions of the system, this is done automatically.

Step 6. Click Start
The scan will begin. The process may take a long time and slow down your computer. Start it at a time of day when you are not using your machine.
If there are any errors, Windows will try to resolve them automatically. You will receive a report at the end of the scan to inform you of the results
Advice
- Always double check before doing anything. Improper handling and you risk losing your data permanently.
- Google is your best friend. Use it to find help or other recovery methods.
- Find a tech site and politely ask for help in the right forum. Someone will probably agree to help you.
- Remember that you cannot repair a physically damaged hard drive, just as you cannot repair a physically damaged processor. Leave that to the professionals.
- If you are having trouble with an old hard drive, try recovering your data and purchasing a new hard drive to save it. The lifespan of hard drives generally does not exceed 5 years.
- Consult other sources if you are having difficulty.
Warnings
- Format a hard drive only if you are sure it works and does not contain any data you need. Formatting will remove all of its content.
- Take care of your hard drive. Do not drop it or shake it after taking it out of your computer. He is very fragile.
- Take extra care with laptop hard drives. While they are designed to be choppy and tossed around, they are thinner and smaller than desktop hard drives. If the case is bent or broken, it may not be possible to reassemble the hard drive.
- If you backed up your data to CDs or DVDs during the recovery process, please make sure the burn was successful or you will lose your files permanently when formatting the hard drive.
- Never open the case of a hard drive. Exposure to unfiltered air and the contaminants it spreads can permanently ruin the trays.