Question HDD won’t show as boot option in BIOS

[Viperajlx]

I just had to replace my motherboard and it finally came in today. I had been working for hours putting everything back together and finally got it up and working. When I got into BIOS I noticed that it only had my NVME M.2 SSD as a boot drive option. When I originally built my computer a year ago I didn’t install windows onto the M.2 how I was supposed to and I installed it onto my HDD. My HDD has all of my programs, games, files, etc. along with windows. I’ve tried to swap out the SATA cables on the HDD and all but it didn’t work. I’ve also tried enabling all the ports in BIOS and still didn’t work. I’ve been trying to figure this out for hours. My computer is a custom built desktop. My motherboard is the MSI B550 Gaming Plus.

 

[kurdtnz]

When swapping out motherboards, it's advised to do a fresh install of Windows.

 

[DSzymborski]

Have you tried other SATA ports for the HDD?