Welcome to the community, Clearvision!
@thejackal85 has a point, you should check
Disk Management and see if and how your secondary HDD is recognized there. Another place to look for your drive is BIOS itself. Check if it's listed in the connected SATA devices.
If it pops up anywhere, you should definitely run the HDD manufacturer's brand-specific diagnostic tool or
a third-party alternative to determine the health and SMART status of the drive.
I'd also strongly recommend you backup your data from it somewhere off-site as soon as you can access it.
Keep us posted with the troubleshooting.
SuperSoph_WD