Data Recovery
Data Recovery software tools cover almost every situation.
From a lost password for an Office application to undeleting files from an emptied recycle bin; simple data recovery software will usually do the trick.
Recovery from drives that can not power up can only be performed by trained recovery engineers. These engineers will move your damaged drive(s) into the clean room, where their equipment can copy a duplicate drive for inspection. This is done to determine where the data is actually corrupt and where it is not. This is almost always a procedure that takes hours of continuous work.
Getting a team to evaluate the problem and sending damaged drives and media to their laboratories is just part of the problem. They also need to be skilled at rebuilding rare or obsolete equipment.
Any write operation can overwrite deleted files for good. So, in case of suspected problems: don't write anything to data drive, don't run any disk utilities such as chkdsk and defragmenters, and don't reboot your computer - Windows can automatically run chkdsk during start-up procedure.
Free downloads restore files of usually less than 100KB, and are invariably trial versions of limited duration (15 days for instance).