Question HDD and SSD not being recognized by PC

[Churp]

Hi there everyone!
I just completed my first PC build and I'm running into some problems.

When I first booted up my PC and the BIOS, it showed only my SSD in the Boot Menu (970 Evo NVMe M.2). I double checked all my wires and plugs and realized my HDD wasn't fully plugged in. I fixed that then rebooted the BIOS and then my SSD disappeared. As well as my HDD not being recognized in the Boot Menu but it shows up in my SATA Information. (Shown in picture). I've been tinkering around in the BIOS settings and looking at other forums for help but nothing has worked. Another note of information, I randomly decided to unplug and re plug all the cords connecting to my HDD once, and it showed up on the Boot Menu, thinking I fixed it I tried to tinker around to fix the SSD. But after I changed a few things the HDD disappeared again, I changed the settings back to default and the HDD still wouldn't appear and I'm still unable to make it reappear in my Boot Menu.

I really appreciate any advice and tips given, thank you!

(PC BIOS Screen)

https://imgur.com/a/NRzPzLU

View: https://imgur.com/gallery/NRzPzLU

 

[Jordan42]

I would try only plugging in the ssd install windows then go and try to plug in the hdd.

 

[Churp]

I would try only plugging in the ssd install windows then go and try to plug in the hdd.

I don't know what I'm doing wrong but I downloaded Windows onto a USB and installed it onto the SSD for my new PC, and the PC ran into a bunch of downloading errors. So I decided to wipe my SSD and try downloading windows with the CD and ran into a bunch more problems. After trying to fix those I'm just stuck on this problem with Windows giving me the Error Code 0x0c0000225. I've tried some solutions but nothing is working...