There is a main board led display, and I think it says 85, but I don't know what that means.
From the board user's manual:
"85 Display errors to the user and gets the user response for error."
It seems that the board is trying to display some error to you and awaiting for your response.
Try to "clr CMOS" with the key located on the main board backplane, and then boot again, using the reset button.
Did you manage to hear the beep after powering it up? You might want to try the system with some "older" PCIE graphics to verify it is not some BIOS incompatibility... I didn't flash my main board, as I don't have to reboot my system that often, but that might be one of the solutions for such behavior.