When a file is saved on a computer, the data is stored on the hard disk platter's magnetic coating. This magnetic coating on the platters is the 'glue' that keeps your data. Any damage to that magnetic coating means that there is data loss as each piece of missing coating contains data. So a platter missing a little bit of that coating has a better chance of a successful data recovery as opposed to a platter that has had massive amounts of that magnetic coating removed or destroyed.
Hard Drive Failure Parts
Typical hard disk components that fail include:
The Human Factor Accidentally deleting files, formatting the wrong hard drive, and attempting to upgrade you operating system only to have it fail are common issues that come up. Also, as careful as most people are with their laptops, a small drop from the couch to the floor or down a flight of stairs, is the type of forceful jarring to the disk drive that could cause serious damage to the hard drive platters.
Viruses E-mail typically are the way most viruses are spread from computer to computer. Also, visiting questionable websites that have scripts, malware or spyware waiting to comprise your system and put your data at risk. It is recommended to run the most recent anti-virus software to protect your data from this sort of data loss and to reduce the need to require data recovery service.
So how do you protect yourself from loosing your data? Back it up! However, should you still require data recovery services, be sure to use a company that specializes in hard drive data recovery.