Thanks for the replies, HoboCannibaL.
The thing about the original SSD 80gb is that it started giving me headaches showing up (as in, claims there's no valid boot device at system boot up, and then showing up in bios at least most of the time, but just giving me that same message when I try to directly say to boot from it)
... it started doing that before I'd even done anything with the new one other than hook it up to an entirely different cable, which I freed up by removing a very old HDD further down the case.
And this isn't the first time, when the system was stable it was stable but when I was first setting it up? and I believe maybe a time or two since just randomly... yea, this same crap happened.
This ASUS UEFI bios thing seems to like to just suddenly decide there's an issue when nothing's really changed.
I've found people discussing it online, some were saying you had to reinstall windows on the drive, others said (and this was my experience) that just unhooking it and replugging it in could fix it (that's fixed it for me before, but not always)
I haven't tried much with it lately because I'm still sort of sitting on top of a Recova scan that took me like 12 hours to get... and I'm hesitant to reboot, I need to soon but... I'm also hesitant to create for myself a bunch of headaches with the drives showing up and not showing up again, particularly before I fully understand what to expect.
What I really need to know is how both of these SSDs should be hooked up and set up in the bios in order for me to see both, have access to both at the same time, but have the new one be the C: drive as it is currently. I don't want the old one to try to reassert it's C: drive status and screw everything up. I need a basic understanding of what behavior to expect... so I can extract data from that old drive safely.
I'd ask about trying to set up a dual boot with both of them but I feel like that would just be headache city and I wouldn't need it for long anyway.