Nothing Showing Up in Boot Option Priorities

[Cherry Pauper]

I have a desktop PC that I built that all of a sudden stopped properly working. Instead of going into the Windows 8.1 operating system, it goes into the Asrock UEFI. At first, I thought that there was a problem with the hard drive since it wasn't showing up in the Boot Option Priorities (nothing shows up under BOP). However, I plugged in the "faulty" hard drive into a working computer A and it was able to identify it. However, when I went into the boot priority menu in computer A, the hard drive still wouldn't show up in the BOP, but showed up as storage when I went into the OS to access the files. I then took my working hard drive from computer A (not the "faulty" one) and plugged it into computer B (the one I'm having issues with) and the hard drive from A still wouldn't show up under BOP. I tried loading default settings, but I still couldn't get it to show. To be clear, NOTHING shows up under BOP. This is what my UEFI looks like for computer B:

https://puu.sh/irk7K/1ca5efdadc.jpg
https://puu.sh/irm3p/5c853e9171.jpg

I've tried using multiple wires and I still don't get any results. I realize that there have been multiple posts on the matter, but none have helped me. Any ideas?

BACKGROUND: My PC was running properly for 6 months prior to the incident. The first time this problem occurred, my PC went into a black screen telling me that it couldn't find the OS. To solve this, I moved my hard drive's SATA connection to a different port on my motherboard and my PC ran fine for 10 days and then this new problem occurred.