Your motherboard support site:http://www.asus.com/Motherboards/P8Z77V_DELUXE/
1) unhook all HDD/SSD's (leave DVD drive)
2) remove BOTH graphics cards and use the onboard DisplayPort or HDMI if possible (if your BIOS is pre-set to iGPU perhaps the video is actually there. Probably not... ).
3) *Your motherboard has both:
a) LED indicators next to key components (see motherboard manual)
b) ERROR CODE LED (manual 2-23)
You should see these CODES changing as tests are run in POST, then show a SINGLE CODE.
4) Is your CPU fan spinning up at all? If so, does it stay spinning?