Computer data can become inaccessible by two fundamentally different categories of causes: Data loss due to physical harddisk failure and data loss due to logical corruption. At Cyberstar Data Recovery Service, we only concern ourselves with the latter category.
Generally, this term refers to situations where the computer is unable to make sense of the bits and bytes, logically constituting a file, but physically distributed randomly throughout the disk. These situations are usually caused by the computer's index system - or file allocation table - being damaged or corrupted. The data are still there, but the computer is unable to recognize them for what they logically are.
When a user deletes a file, the actual data are not destroyed, but the file's entry in the file allocation table is removed, telling the computer that the areas that previously contained parts of that file, are now available for new data to be stored.
When a file is saved to a hard disk, the computer does not search for a continuous space large enough to contain the whole file, but writes bits and pieces of the file randomly throughout the hard disk surface. Where ever the write heads happen to be when the save command is received, that's where the new data will be written.
Thus, the original data remain in place until another set of data is randomly stored there. Consequently, as long as the deleted data have not been overwritten by new data, they are available for recovery. However, once parts of a deleted file have been overwritten by new data, it is virtually impossible to recover it.
You may think: Well, if I just save my new data to a USB-stick, I can continue working. But you're wrong. Operating system and loaded applications continuously write temporary files and scratch to the hard disk.
So, have you accidentally deleted some important data and emptied the waste basket? Turn off that computer and contact a professional.
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