Problem with Boot Priority after clean install

[Blue Blue Sky]

Hello guys,

I am in a state of emergency after reinstalling Windows 10 yesterday.

My specs

Spoiler

ΜοΒο: Gigabyte AB350M Gaming 3 (rev. 1.0)
CPU: AMD Ryzen 5 1600 Box
GPU: Gigabyte GeForce GTX1060 6GB
RAM: G.Skill RipjawsV 8GB DDR4-3200MHz
SSD: 2x Samsung 850 Evo 250GB
HDD: 2x 500GB
OS: Windows 10 Education

What Happened

I recently switched from Intel to AMD (new CPU, MoBo and RAM), and because at that time I was very busy, I did not do a clean install of Windows 10 after the hardware upgrade (everything was working fine).
Yesterday, I finally found some time and did the known process (done it countless times before). I downloaded the Windows Media Creation Tool and followed the option to install Windows 10 using a USB drive.

As you might have noticed, I have 4 disks. Two SSDs (One for the OS and one for Program Files), and two HDDs(files). To be safe, I decided to erase the SSD that contained the Program Files and install on it a fresh copy of Windows 10, so that in case of failure I still have my old Windows 10 drive (thank god I did that). I erased all of the SSD's partitions and selected the final Unallocated space in which I successfully installed Windows 10. I also installed updates and some basic programs.

The Problem

I noticed the main problem while the system was installing and had to restart several times. When it restarted, it would not boot by default into the SSD where the installation was happening but instead it would boot my old Windows 10. So I had to manually boot the correct SSD on start-up using F12 to show the booting list. After Windows 10 were successfully installed the problem persisted, and that's when I said "That's it! We're going in!". With my basic knowledge of computers, I entered the BIOS and tried to find and fix the "Boot Priority" option. That's when I realized that the SSD with the fresh install was not showing up on the "Boot Priority" list. I would only get my old SSD and a random HDD. I could still manually boot on my new OS so I took the day off of the problem and decided to start fresh the next morning.

Unsuccessful Solving Attempts

Today I woke up and started working on solutions, and I have to admit that I feel like I'm in a worst place than yesterday!

So, the first thing I thought I'd try, was changing the order of the SATA3 cables on the board. Nothing changed.I put them with numerical order (0, 1, 2, 3. SSDs on the first two and HDDs on the remaining). Again, the disk in question did not show up on the Boot Priority list. Then I tried disconnecting all other disks. This time it booted alright, but I got this message:

So now, although the SSD does appear on the Boot Priority list, when I try to boot it, I get the message above. I have plugged the disk with my old OS and while I can see the disk on "This PC", I cannot boot it on start up.

I'll also leave some photographs from my BIOS settings. Maybe they contain needed information:

Spoiler

Any help?

Thank you, and sorry for the long post.

 

[cin19]

1) Make sure the boot SSD is connected into the 1st SATA port.

2) Make sure disconect other SSD/HDD, when you install the win10.

And try to clean installation one more time.

 

[CountMike]

You probably fell into trap when windows install BOOT on one disk and C: is on another.Disconnect all other but system disk and try new install on it during which you should choose to delete all partitions on it and let Windows make as they seem fit.

 

[Blue Blue Sky]

Thank you both! I did what you said. I disconnected every other disk and reinstalled. Worked like a charm.

 

[CountMike]

Great, windows like to make a mess when they see other disks with active and system partitions. That is specially a problem when going from legacy BIOS to UEFI and 2 or more disks with UEFI partitions.
Now you should get rid of all such partitions on other disks if there's any. Save a lot of space too, you can merge them with other partitions.