Originally Posted by vierendelen
Nope, the drive in question is not recognized on boot up.
There are two currently installed, both F3's xD
Okay, that is most likely your problem (My brand is also Samsung). My motherboard has 3 different sata controllers, I had to plug each of my 3 different hard drives into a different sata controller and that fixed the problem for me.
Just for testing, you could try to unplug your first HDD and see if the bios recognizes the others, and then you will know that it's not a problem with the harddrive but rather conflicts. I'll look for a way to get two of the same hard drives on the same sata controller.