said... Connect your hard disk with another pc, if it shows the data, then it's good otherwise opt for a data recovery software and install in the hard disk whose recovery is to be done.
Most of the companies promise to recover data, but we should be aware that data can only be recovered if it is not overwritten. Once data is overwritten by any other data, it can not be recovered by any data recovery method.
So before buying any data recovery software, we must check the preview of the recoverable data. If required data is shown by the software only then it is recoverable. We should opt for such product which shows the preview of the recoverable data in the free version.