If you can't boot at all then it is a sign that the drive might have totally died.
A couple options:
1) Double check all cables are correctly installed
2) If you have an external HDD/SSD enclosure or dock like
this one then you can pull the drive and see if it can be accessed at all as an external drive on a different PC.
3) If you have a spare USB you could create a live LINUX install on the USB, boot into the Linux OS, and then run the available disk diagnostics on the Linux flavor you chose. Ubuntu would be a good choice just because there are so many tutorials on how to do exactly this process.