Most probably you are dealing with a BAD SSD or SSD Slot latter would be worse.  in BIOS > System Configuration > m.2 PCieSSD /SATA-2 should be enabled.  If already is  Remove power cable Open back panel and disconnect battery cable, now hold the power button for 30 seconds. If you are luck this will fix it.    Else RESEAT SSD (unplug and replug )   Test SSD on another system  Depending on the result on last step, motherboard or SSD  
When I powered up my Inspiron 3793 today, it booted into Linux on my Samsung EVO SSD, and not the PCIe NVMe drive, which is the default.  Windows 10 Pro is on the PCIe NVME drive, and should boot by default. I went into the BIOS, and all the SATA devices are enabled, but the only drives which are detected are the CD/ROM and the Samsung EVO SSD. The BIOS reported -none- for the SATA 2 device, which SHOULD be the PCIe NVME M.2 drive. Where has my drive gone to?  I have tried rebooting and running the built in diagnostics, but nothing is reported wrong. I tried turning the SATA 2 port on/off, but it makes no difference. As a side note, the drive is not detected by Linux either, but it used to be, until today! Any ideas?
PCIe NVMe M.2 drive has disappeared from system