Hi Sandstroem83.
So I assume this SSD has already been used with that computer, but please let me know if this is the OS drive from a different system.
Did you encounter any errors before this issue occurred? Do you need to recover data?
I'd suggest that you try the SSD with a different SATA port and with different SATA cables, or even better - with a different computer if possible. You could also try updating or resetting your BIOS/UEFI, to see if that fixes things up.
Please let me know how everything goes.
Boogieman_WD