Hey there, Lord_Seti!
I'd follow @popatim's troubleshooting advice and check how the HDD appears in Disk Management. Do you have any data stored on that drive? Were you able to access it previously? If it doesn't show there or in Device Manager, I'd recommend you to use a different SATA cable and try plugging the HDD to another SATA port on your motherboard. It is also possible that there is a shortage of power supply to the drive, which would explain why you encounter issues with the proper detection.
However, if it's a brand new secondary hard drive for your rig, then you most certainly need to
initialize it (as it was already mentioned) and then
partition & format it from Disk Management.
Hope this was helpful. Keep us posted!
Cheers,
SuperSoph_WD