Repairing hard drive partitions on a corrupted hard drive is a dangerous procedure. Even if you apply the greatest toolkit and are totally certain in your deeds, you are still risking your data shall something go wrong. Alterations that may be done to the damaged disk are irreversible. You must remember that it is really simple to overwrite the structure of essential information about your hard dist. First of all the substitute must be created before the beginning of the recovery procedure.
You may find the other way of file restoration procedure that can be even more harmless and easier and it does not need to have backup. There's a system of complete binary image that you can use to your drive or the partition that is being recovered. After that you can make a recovery with the various settings on this image for as many times as you need. That is the purpose of data recovery software.