R3 15 nvme drive visible in bios but not windows

1. came with a 1tb disk. I swapped this out for my samsung 120gb ssd which already had my version of windows 10   2. I then added an intel 512gb 'SSD6' drive to which I intended to install my Steam games. Sadly the drive is not visible at all in Windows but shows in the bios. I tried installing the intel ssd management software but even this does not see the drive.    3. The default sata setting is 'raid on' and I have no idea if this is important. Any guidance welcome, I'm sure I'm just being a dunce.

1. This is not advisable unless you mean you cloned it or used and Image-File.
 
2. SSD still needs to be Initialized in Windows-10 Control-Panel/ Disk Management.
 
3. I don't have any NVMe drives, but pretty sure I read that system must be in AHCI mode to get that part working. However, sometimes you can't switch from (single disk) RAID to AHCI without re-installing Windows.
 
Macrium Reflect (free) is good insurance and sometimes a time saver.

Many thanks for your reply. I did actually use an existing copy of Windows 10 pro which I have been running on my desktop for the last year or so. Perhaps this is an issue? I didn't realise it might be a problem to do this. I installed all the Alienware software and drivers from Dell and it all works beautifully, aside from this particular issue.

I tried disk management as a first step and the drive did not show there, I then tried to list the drives via the command prompt to see if it was visible there and again, it does not appear.

Indeed I cannot switch from 'raid on' as it won't boot.

I may simply start over from scratch, my samsung SSD has only ever been used for boot rather than storage so a fresh install wouldn't cause me any real problems.  

I'll give it a go now.

:)