I got a new case for my prebuilt computer which was a Hp Envy Phoenix 860-160se and I didn’t like how small the case was. So I decided to get a new case which was a Kopplen Z3 ATX case and I have a mATX mother board which is the Hp Viking X99 (it came with the prebuilt) The old case worked perfectly I just wanted more space but when I plugged everything in it powered on and the fans start for 1 second then stop in loop. Only the power button led lights up for a second then turns off when the fans stop. I was having a lot of problems finding which switch belongs where because the prebuilt MOBO had no manual or any indications of what went where. I the Power Button and the USB 1/USB2 and the audio seemed to all be plugged in fine. The plugs are in perfectly fine and the GPU PSU CPU and RAM are all working. I don’t know if mounting the motherboard could be the problem. But I’m very new to this so I am not sure