A hard drive's file system may become corrupted or damaged due to a virus or software malfunction, but this is not a true drive failure because in most cases you can reformat the drive and reinstall the operating system and everything is back to normal. Hard drives fail due to a malfunction in their mechanical or electrical components.
The following picture illustrates the major components inside a hard drive:
The following is a list of the most common mechanical failures that can happen.
1. The spindle motor can malfunction. The spindle motor works much the same way that cd-rom or dvd player spindle motor works and is located in the middle of the hard drive platters. In a hard drives case, it's job is to spin the platters.
2. The read/write heads malfunction or the actuator arm malfunctions and prevents the read/write heads from reading the data stored on the hard discs (the platters). The picture below shows a closer view of the platters, actuator arm, and read/write head.
3. The hard discs themselves can become damaged by rough handling (dropped) or can in some cases become scratched by the read/write heads if they touch the disc.
4. On the back side of the hard drive case you will see where the cable and power supply plugs in and you will also see where the jumpers are. These contain small pins and can easily be bent or broken.
5. Another problem that can occur is the cables and ribbons themselves become loose and do not make a proper connection or the cable themselves can become damaged. The power cable can also become damaged or malfunction.
Picture of an IDE cable.
Picture of a SATA cable.
Hard drives can also fail due to malfunctioning or damaged electronics on their circuit board.
The most common electrical components to malfunction are Transistors, Capacitors, and Resistors. Power surges are the common cause of these small components to fail, so remember to make sure you are using a good surge protector or a UPS system for your entire computer system. A good policy is to always unplug your computer system from outlets when a storm is capable of producing lightening.
It is also important to remember that if any of these failures happen, it will be cheaper to replace the drive for a new one. You can return a hard drive to the manufacturer to be fixed if it is still under warranty. Read your documentation and warranty information carefully
if you purchase a new hard drive to upgrade/replace your old one.
The following picture is an illustration of where the hard drive is located inside the computer case. In this case, it is a SATA hard drive.