Hi shinobirain and Welcome to ROG. Unfortunately it is a big flag and can be one of many things.
Qcode 99 is "Super IO Initialization" and IO meaning anything connected to the board by any interface is not initializing.
If you have just built the system, then it is saying a device is not connected properly or there is a lack of power to a device causing the IO error.
First check all cables and components are seated flush and level and aligned in parallel with Pci-e slots and your DIMMs seated correctly.
Should the condition continue, you will have to Bench test outside the case and reapply your TIM after checking for bent pins. Test with minimal configuration, till you post successfully or identify the failing component.
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My System Specs:
MB:ASUS ROG Crosshair VII Hero/WiFi GPU:EVGA GTX 1080 sc PSU:Corsair AX-1200i
CPU:AMD R7 2700X Cooler: Corsair Hydro H115i Case: Corsair Carbide 780t
Memory:G.Skill TridentZ F4-3200C14D-16GTZR SSD:Samsung 500GB 960 EVO M.2