Resolved HP Pavilion DV7 laptop-one HD or two?

I just bought a used HP DV7-6195us laptop from a private individual who attempted to upgrade it from Win 7 to Win 10. I reverted it back to Win 7,
but noticed that under Device Manager> Drives, it shows two Toshiba MK5076GSX SCSI Disk Device(s). Yet, under computer, there is only one 500gig C: drive.
Looking on amazon dot com, they advertise the laptop as having one 1TB dual drive. I don't know what a dual drive is. Further, most places that describe the laptop call the drives SATA devices, not SCSI as showing in the Device Manager.
I haven't unscrewed the bottom of the laptop to see if there are in fact two physical drives installed. Compounding the confusion is the fact that there are a number of DV7 laptops with differing six character suffixes, all with different specs.
The installed OS is Windows 7 Premium 64bit.
I guess my questions are: are there two drives and why can I not access the second one?
Also, does having device manager identify the drive(s) as SCSI have anything to do with the disappearance?
I did a google search for the Toshiba model drive, and the Toshiba website does identify the drive as being SATA, not SCSI.

 

2 hard drive bays

Support.HP.com > HP Pavilion dv7-6195us Entertainment Notebook PC Product Specifications

Google.com > MK5076GSX

 

Please disregard my query. Problem solved.

After posting my questions, I did some more searching on Google, and stumbled on some related posts.
The solution was to right click Computer, select Manage, go to storage.
I found the second drive sitting there without a drive letter and labeled as Unallocated. I gave it a letter, formatted it, and now it shows up under Computer.
Thanks to all who viewed and replied.