As Drlucky said. Best option is to test it on a second PC as an internal and external drive. if it doesn’t work then the drive has failed.
This is a pretty common problem in most SSD drives and when you get a replacement test it as an external medium for a while and update firmware.
You can get more help here: http://www.tomshardware.com/answers/id-3020977/ssd-disappeared-bios.html
