EZ debug cpu light on, im stumped

[taglodisamazeballs]

So basically I just built my brother a new PC. i7-8700k and the MSI z370 carbon pro are the main bits here(but its 2*8gb corsair vengance if the ram is useful). Tried to power it on, no luck, nothing outputting on HDMI or DP, so I looked inside at the LED's. The CPU debug led was on. I've tried reseating all the ram, in every configeration with both sticks, tried reseating the CPU, nothing. Bare in mind no bent pins or signs of damage(I looked over it when I reseated). Any idea guys?

 

[Greeko85]

All power connectors plugged in properly/securely? CPU cooler installed as well? Have you tried resetting CMOS?