Sometimes an NVMe card may become slightly loose in transit, or may need reseating .
The NVMe card is your fast SSD where windows is installed so if this card is not fitting correctly your PC will fail to boot.
With the PC turned off, unplugged and on its side, open up the side glass panel and look for the small card indicated by the rectangle in the picture below
The arrow points to the retaining screw.
Undo the retaining screw and the card should pop loose.
Remove the card and carefully wipe the gold contacts with a soft cloth
Blow gently into the slot on the motherboard to clear any dust that may be in the slot
Then replace the card in the slot
Please note the little slot inside the slot which needs to line up with the groove on the NVMe card
Push the card gently into the slot until it is fully inserted then screw the retaining screw back in.
This should now allow your PC to see the card again and boot into windows properly.