I just got a Sound Blaster Z and installed it (hardware-wise) but my computer won't detect it. It doesn't show up in device manager, or in my BIOS when I examine the slots on my motherboard. I've tried it in the pcie 3.0 x16 slot (which is two slots down from my graphics card, which is in the first pcie 3.0 x16 slot, also coincidentally hogging up enough space to render the x1 slot above it completely useless), and then moved it to the pcie 2.0 x16 slot at the bottom of my motherboard, but both times nothing was detected, and it was shown as empty in the bios (and device manager). The sound card itself lights up when I turn on my computer, so its not completely unresponsive, but its just not being found for some reason.
This is my motherboard: http://www.asrock.com/mb/Intel/Z77%20Extreme3/
I also have an EVGA GTX 760 SC, 8 GB DDR3 RAM, and an i5 3570K.