The drive was showing up fine in multiple computers, Windows 98, XP, and 10, but all of them showed that the 40GB drive only had 3GB and was completely empty of data.
I tried several partition recovery programs which detected the lost files, but they were unable to actually recover the files due to drive error (can't remember specifics).
TestDisk detected the same lost files but also couldn't recover them because it said there was a geometry mismatch, the heads was set to 255 and it suggested it should be 128.
I changed the heads to 128, rebooted, and the drive detected fine but TestDisk was still reported a geometry mismatch and was unable to recover files.
From there I changed the cylinders, heads, and sectors to what was printed on the HDD. This made it an 8GB drive but it still rebooted and detected fine in BIOS, but still showed a geometry mismatch in TestDisk.
That's when I modified the sector size from 512 to 2048 because I was out of ideas and rebooted. From then on the drive was not detected in any of my computer's BIOS (3 different systems, P3 500, P4 2.4, C2Q 9650 all different cables). I have double checked jumpers and they're fine, unchanged from when the drive was detected.
I really don't think the drive death just happened to coincide with the change of sector size, I think it's definitely related. Everything that was wrong with the drive I should have been able to fix with an FDISK and reformat based on previous experience until I messed with the geometry.
Casio BE-300 Advancement Society alumni