Many times people could have saved their data before the hard drive actually became unusable, yet they failed to do it because they didn't realize what was happening to it.
One such warning sign is when your disk makes some strange noises during work, or you notice your computer crashes quite often.
If any of these has happened to you recently, this is a sure sign that your hard disk is failing you.
This is why the first thing you need to do, as soon as you notice any such irregularities, is backup your data.
Use an external drive or a USB stick to copy all essential files on it.
Of course if you have more data than the flash drive can hold, you will need an external drive to store everything that you had on your original one.
Depending on the type of failure, you could be experiencing either actual physical or software failure.
If it's a hardware issue, you will have more problems getting back your files than if you're dealing with a software problem, such as recovering from a virus or from scrambled data or something similar.
Software failures allow in most cases a complete recovery of your entire data and it won't cost you that much either.
If, on the other hand, you experience a hard disk crash, you will need some forensic expertise to get back your files.
You will need a service that can do it for you, but be prepared to pay, as it will cost you.
This is because the company has a special data reading device to do the job which cannot be easily used by regular folks like you and me.
This is why at the earliest signs of any drive malfunctioning, don't do the mistake of leaving it up till the last minute when you won't even be able to boot up your computer anymore.
Back up your files at the earliest possible time so you can then easily deal with the rest.
Once you have your data backed up, you can decide whether you want to spend the money on a data recovery service or you're better off buying a new drive (which let's face it, will be much cheaper anyway!).