Computers have evolved substantially during the last few decades and their storage capacity has soared. The first computers had only external memory on which you could store your operating system, the 2-10 files you worked on or the miniscule game you were playing (which were stored entirely on a floppy disk or on a tape). Hard drives have now reached amazing storage capacities to terra byte levels, but nonetheless, they are mechanical systems that are operated by the means of systems and because of this, they will fail in time.
If you start your computer and you see a friendly error message regarding your hard disk, you do not need to panic because there are solutions that you can gradually apply to verify if the hard disk is malfunctioning and also to recover your data.
The first step you need to take is to access your BIOS and in the advanced settings section, you need to see if the SMART drive reporting software is enabled or disabled. If it is already enabled, you should disable it for a couple of days so that the system boots normally and to see if the error persists. A reason for the error message might be an inconsistency between the hard drive, the motherboard and the SMART drive which might be outdated or it may not have complete resources with the hard disk. Although useful, the SMART drive has a large margin of error and it might give inconsistent error reports when there are no problems from the physical or the configuration point of view.
Also, in these circumstances, I recommend that you return to the standard BIOS settings. To do this, you need to restore it to the default settings. It can be accessed by pressing F10 in most BIOS environments, but there might be another key combination depending on your system. After you have done this, save the changes and exit. During the next few reboots, you need to monitor if the error message appears again.
The second step is to look at the hard disk itself. You need to remove all the electrical power cables. Open the case and closely examine two aspects of the hard disk. First check if there are any signs of a possible short circuit near the disk drive. The other is that all the connectors are correctly plugged especially the data band. Also examine the data band if it is intact and check that it does not possess any tearing. In IDE mostly, in time the cables begin to shred and this leads to a series of malfunctions. It is advisable that you try to replace the cable and see if in the error appears again.
The third step is to begin salvaging data and to contact a hard drive recovery company in the domain. There are reliable service providers which will give you a complete analysis on your situation and will salvage all your data for a convenient price, especially if you do not have the time to do it or if you do not have the expertise yourself.