Deceased dad's old hard drive showing as "unallocated" - no partitions found on scanning, please help.

Hi all - my dad passed away from cancer quite suddenly a few years back, and to cut a long story short, I have finally got hold of his old harddrive (An 80gig Samsung SP0842N). It doesn't appear to be physically damaged in any way, but I can't vouch for how it's been stored for the last 2 years. My dad was a musician and artist, so there is (hopefully) a lot of data on the drive that I would dearly love to get back if at all possible, including family photos and songs we played together etc... - Anyway, to the problem: The drive is attached to a laptop running Windows 7 via a SATA/IDE USB adapter. There are no unusual noises on powering it up. The drive doesn't show in My Computer. The drive is recognised by Disk Management, but shows as "Disk 1, Basic" totally unallocated (size shows as 74.53GB). I am unable to assign a drive letter to it or mount it. I have created an image of the drive as it is (if that would even work on an unallocated drive - maybe I've just copied 80gig of unusable space) and I have followed a few tutorials with programs such as "Find and Mount" "Test Disk" "R-Studio Data Recovery" "Spin Rite" and "MiniTool Partition Recovery" amongst others, with no success, although this could very possibly be down to my lack of expertise and not wanting to do the wrong thing and lose any data there may or may not be (while not a novice, this kind of stuff is at the limits of my computer knowledge). I'm willing to pay for data recovery if that's necessary, despite the expense, but I'm not yet convinced it's a mechanical fault and if there is any way of getting the data back without shelling out hundreds of pounds, that would obviously be preferable. I have searched this site (and many others) for someone else with the same problem, and I can't seem to find an answer. I am more than willing to do pretty much anything to try and get this data back - any advice, or walkthroughs would be HUGELY appreciated - the memories I might get back are totally worth any time and effort on my part. Thanks in advance - I'll try and be as informative and helpful as possible. Many hopeful regards, Chris