Ok how big in size is the hard drive.
Was it used in another system as a boot drive prior to getting the SSD drive, or used as extra storage.
If you go into the bios and it is detected there with the right size make and model it`s working.
If not it means looking in the bios to see how many Sata ports are enabled.
Also check that both Sata chip sets are enabled in the bios.
If a new board you should have an option of an Intel, Sata chip set and a ASmedia.
The board can have mixed types of Sata ports, and half are divided between the two Sata controlers in the bios.
So if the Intel or Asmedia chipset is not enabled it will not show in the bios or when booting in windows at my computer.
Some sata ports can be mixed in speed also 2.0 devices and 3.0 device HD`s.
If you plug a 2.0 into a sata port that is 3.0 and does not have fall back to 2.0 the drive will not show till it is connected to a 2.0.
If the second hard drive is new, run windows setup with it connected to your system and format it first.
The drive will not be seen in windows till you format it to NTFS or GPT.
After that abort the windows 8 installation restart the machine, booting off the ssd and the second HD will show in windows.
You need to format every drive if new, because it comes in raw data mode, formatting enables it to be seen in windows.
BTW if you added the drive and used Disk man.
You need to re scan for disks from the pull down menu to see it to refresh the virtual drive list. Once it shows up in the window simply right click and format it.