these bords have new bios for the new cpu codes. you have to use the usb flashback on the back.you dont need to boot the mb just have power to the mb. http://dlcdnet.asus.com/pub/ASUS/mb/LGA1155/P8H77-M/DE103_Z77_H77_Series_BIOS_Renaming.pdf
just use a usb stick and put the file on the root dir of the usb stick and hold the flash back button in till it starts blinking. if the file is named right when the flash starts the blinking speed will change then the port will go out. also check on the video card you have all the power connected and on the mb you have the 8 pin power connected. i would start also by pulling the video card and just seeing if you can get video from the mb.