In a nutshell: My mobo's SATA controller started to fail over the course of a few weeks, so I finally shut down my computer, disconnected the four drives, and fixed the SATA problem. Now I have a new mobo (new computer, really) and as it is a SFF PC, I bought a USB3 HDD dock to manage extra hard drives. Of the four original drives, 3 out of 4 are readable. Of course, the one that Windows is saying "needs to be formatted" is the one with my most important files on it.
I started up testdisk, and did the basics:
1) Selected the media
2) Selected "Intel"
3) Selected "Analyse"
4) It found two identical partitions right off the bat:

5) Ran "Quick Search," and it found two partitions:

6) Hit "Continue" and suddenly it couldn't find ANY partitions:

7) Hit "enter" to continue, and it reinforced that it could no longer see the partitions it had just seen:

I'm running a "Deeper Search" now. Am I on the right track?
I'll add more pics as I progress: http://imgur.com/a/t2Z1b