3. Use data recovery software when the hard drive has a physical problem

This is a common mistake, if you use data recovery software in these situations you are risking losing data for good. If your hard drive is making clicking noises or if it was recently dropped the data loss cause would almost definitely be a physical problem which would require the services of a reputable data recovery company. If you are in doubt speak with such a provider, as they should be able to advise over the phone what type of fault(s) your drive has likely suffered.

4. Replacing parts of the hard drive

If your hard drive has suffered a failure it may just need a spare part or two. However, it is not as easy as it seems – there are so many intricacies that come into play when changing parts on a hard drive, for example are you sure that your new circuit board’s firmware is compatible with all of the other parts in the drive? In addition, it is important to consider the environment that this is done in – all reputable data recovery providers will have a cleanroom with minimum standards. In these cases it is best to leave it to reputable data recovery professionals.

5. Writing your data off for good.

Another common mistake is that when the computer has suffered some serious accident (like be broken in a half, or is burned) many people think that they can’t recover their data. In these cases, again it is best to speak to a reputable data recovery provider, especially one like Kroll Ontrack, who has the largest R+D resources globally.

The moral of the story

Unless you are positive that your data has suffered from a logical or software-based failure then it is best to speak to a reputable data recovery provider.

Reference: http://blog.krollontrack.co.uk/top-tips/5-diy-engineer-data-recovery-methods-dont-work