Skyreach,
When you power your system on, press the key to enter the bios like you have done.
Check to see that any Sata chip sets are enabled in the settings of the bios.
And make sure that the mode set for the Sata ports of the motherboard is Set as AHCI mode.
If the mode is set to Sata it is one of the reasons why the hard drive is not seen in windows install and setup when it asks you where you wish to install windows to, what SSD or HDD. Why they don`t show in the list of detected storage devices window.
Also make sure that CSM mode of your bios is enabled.
And the hardware booting and device detection mode is set to Legacy / Uefi as the selected option.
Save the new changes before you exit the bios.
The other way to be able to see any SSD drives or HDD if you leave the Sata mode as Sata Skyreach.
And run the setup and installation of windows 10.
Is on the page where it asks you where, or what drive you wish to install windows too.
If no drives are shown.
To the left side in blue writing should be the add driver option.
You click on it.
And if using a dvd drive or disk, eject the windows 10 setup dvd.
And then place the driver support dvd that came with the motherboard.
You then navigate that disk for the sata drivers on the dvd disk.
Select them and click next.
It will load the Sata native drivers for the Sata chip set of the motherboard.
Where once done.
The main window where detected drives to install to of the windows setup should refresh and show the SSD drive and the HDD connected to the motherboard.
Once done, simply swap out the Driver support dvd that came with the motherboard.
And insert the windows setup DVD back in the DVD drive of the system.
And simply select the drive you wish to install windows on and click next in windows install and setup.
As long as you check and follow both of solutions I have typed here for you both the SSD and the HDD will show in windows 10 setup and install.
Could I also mention that for the HDD if you intend to use it as extra data storage space Skyreach, before you choose the ssd as the place to install windows 10 on.
Select the HDD and click on the advanced drive options.
Then simply format the HDD.
Then select the SSD drive and click next to install windows.
That way both drives will show in windows 10 once it is installed and running from the SSD drive.
Because if you don`t format a drive first of all windows does not see that extra storage drive.
All drives have to be pre formatted so windows can see and display them in windows explorer, as the drives come in a factory raw state.
Formatting lays down a file system so drives can be displayed and read and written to by the windows os once the os is up and running.
If you get what I am saying.