I tried to boot up a relatively old computer and it would always blue screen at the Windows XP splash loading part. I thought something could just be wrong with the board because it was old so I swapped out the drive into a much newer board with better wires. Same issue. All the Hirens boot disc utilities I used to try to read the drive treated it as if it was unformatted. I was able to run a Data Rescue DD on it completely though, despite consistent read errors throughout the entire drive. So now I have a ~186GB .dd file on an external drive of mine, and I have no idea how to salvage anything from it. I am hopeful, but I can't seem to find anything online about these types of files.
I am preparing to try TestDisk on this file shortly (making a backup first!). I'll let you know how it turns out.
Any suggestions on how to recover any data from this drive would be greatly appreciated! It is not mission-critical, and I have no intentions of spending money to pay some expert to analyze it.