Free data recovery software can be downloaded, but none of them will work unless the system can actually "see" the drive and that the recovery software can read from it. Free recovery software here:
http://pcsupport.about.com/od/filerecovery/tp/free-file-recovery-programs.htm
If the drive has failed however, the only way to rescue any data from it is to send it to a data recovery service, but that is very expensive.
That's why keeping all your files backed up on a second hard drive or on optical discs is so important. Backing up data has never been easier or more affordable than it is today, yet countless people still don't bother to even think about it.
the fact is that all hard drives fail eventually and you have to be prepared for when that happens.