There are several recovery tools you can buy. You will then need to connect the internal HD to another PC as a secondary (not boot) disk. Ideally you would recover the files to a folder on this PC not recover them in-place. Or you can build a bootable USB disk, but that means you will almost certainly have to recover in place.
I've tried Easus and Recuva. They work about equally well at recovering data; however a high percentage of the files were not readable with both of these tools. PhotoRec seems to do a better job at recovering photos but the names were random.
You just asked elsewhere how to format it, if you want to stand a chance of recovering data then stop using it right now and think and plan, and do not write anything to the disk and that includes formatting.