SSD and HDD not detected

Oct 13, 2018
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So recently I bought new HDD to replace my SSD that was too small in my custom built PC. The computer was working absolutely fine before, it's almost like it read my mind. When I turned it off and turned it on its side, I remembered I needed to install Windows on the new HDD, so I turned it back on and the suddenly the BIOS from my GIGABYTE motherboard pop up saying there is no bootable device detected.
I have a SSD that has Windows 7 installed on it, and also a HDD connected through SATA cords for extra space. Neither seem to be visible suddenly to my motherboard and no matter where on the SATA board I plug the cords to or which cords I use, it doesn't seem to want to detect the device. I would test the SSD to see if there was a problem with it AND the HDD, but I don't have an extra desktop to try to plug them up to. I'm not really sure how to fix this problem, if anybody has any tips. Thanks!

-Kingston 120GB SSD
-WD 1TB HDD
-GIGABYTE Motherboard