If you think about what is expected from a hard disk, running all of the time the system is switched on, spinning a glass platter at up to 15,000 rpm with a solid read head floating just above the surface and thrashing about to access data, then you realise it is not “if” a hard drive will fail but “when”.

There are two types of hard disk:

1. Hard disk drives that have failed.

2. Hard disk drives that have not failed yet.

This is not an adverse criticism of hard disk drives, they are amazing bits of kit that do an incredible job, but they will eventually go wrong and if there is no data backup then a hard drive data recovery service might be needed.

Types of hard disk failure.

The disk sounds as if it is spinning up then there is a steady clicking from the drive but the system can never see it.

This symptom covers a range of problems some minor others catastrophic. Within a hard disk is a platter (or platters) that are (usually) glass coated with a magnetically susceptible coating. This is where the data is stored.

To access the data there is a read write head mounted on an arm that can traverse the platter to located the data. To read any piece of data all that is needed is for the arm to go to the correct position across the radius of the spinning platter and wait for the required section of the platter to pass by.

If there is a problem with the read heads, with the platter, or which the electronics controlling the whole operation then the result will be that no data is transferred. the drive will go through its range of re-try operations and the clicking sound is the arm that holds the read heads actuating and re-positioning.

The disk is quiet, no vibration or heat.

This can be the result of one of the problems l detailed above, most commonly though it will be a problem within the controlling electronics and so nothing is happening.

If you do detect some vibration or there is some noise, it could be that there is a bearing seizure. The platter is mounted on a spindle that is allowed to rotate smoothly, and it needs to be very smoothly, by the presence of bearings. If this seize up then nothing will work, or if they start of get ragged then the drive will be noisy and start giving errors then soon it will give up.

My files have disappeared.

If the disk is working find but you cannot find your files tread very carefully and work out what could have happened before taking any action that could make things worse. If the system things that the space your files were using is now free then any use of the system could result in the data for them being overwritten and lost forever.

If an entire drive has vanished then it could be that a partition table has been damaged. The partition table tells the operating system how the space on the disk is divided up. For example if you have a single disk drive but you have drives C: and D: then there is a partition table that tells the operating system which part of the hard drive is used for C: and which for D:. Without this the operating system will just think it has an unused disk.

If the drive letter exists but you cannot see the files then either they have been deleted or the file system has become corrupted. Be very careful if you are prompted to run any form of repair utility. Utilities such as CHKDSK are designed to repair the file system, this can involve a total loss of your files.

Not all permutations of problems are covered here, to get advice as to the likely cause of the problem with your hard disk, and whether a hard disk data recovery is possibly the answer, follow the links to your local recovery company.