While doing this I discovered one of the laptops optical drives is not showing up in BIOS or Win10.
It has power, pops in and out manually, and even spins when you put a disk in it.
I updated the BIOS but this made no difference.
Because I have 5 other identical laptops I swapped the optical drive with another one.
End result, the original laptop does not register the optical drive from a working laptop.
The working laptop does register the optical drive from the original laptop.
So it's not the actual optical drive that is faulty.
Other than a motherboard fault, is there anything else that may be the problem?
And no, they are no longer under warranty.