Need help diagnosing my Fiancee's pc that won't boot, I don't even get a bios screen. I've tried two different motherboards, an Asus B85M-G, and an Intel DH87RL. I've tried two different CPUs, both intel 4790 non-K. I've tried two power supplies, a cooler master 550-watt and a 250-watt unit from a dell optiplex. I've tried 4 different known good sticks of ram, with all slots populated, 2 slots populated, and only one slot populated (switching between each stick of ram). I've tried booting with and without a GPU, an RX580, and I get no video from the GPU or from the integrated GPU. I get a "sufficient power" led from the GPU too, the led would be red if it wasn't getting enough power. I've tried booting with all my peripherals plugged in and with only the 24-pin and 4-pin CPU plugged in. I get no error beeps or led flashes. Booting with no ram will trigger the error beeps and led flashes but otherwise, I get no errors. If there's anything else I should try or something I'm missing please let me know, all help is appreciated. I've tried clearing cmos by removing the battery for a period of time, I even tried booting without a cmos battery. I've even tried using the outlet my pc is using to see if it was a bad outlet but still nothing.