Here's the best way forward.
Power down the PC and disconnect all the HDD/SSDs and reconnect the SSD that is now connected to disk 3 to the #1 SATA port of the motherboard leaving all the others disconnected, then in the PC BIOS set that as the first boot device.
Then using Option Two
of this tutorial mark that System Reserved as the Active partition and do the 3 separate startup repairs in Option One
to make that the System partition.
Startup Repair - Run 3 Separate Times
After that's done you can power down and reconnect the other HDD/SSDs