CPU red light on at boot and stays on and system will not boot

Trex64

TS Rookie
1 year old, self built with Asus 170-A MB all new components at build. Was working fine, then I sent a PDF by email and the screen went blank and the system froze. No keyboard response and no display. All other MoBo and GPU LEDs are nominal. All fans running, but Red CPU LED stays on. I reset memory and CMOS, with no change. Thoughts?
 

Cycloid Torus

Stone age computing - click on the rock below..
Please describe specific sequence and results (lights, motions, sounds) of 'cold boot' from full off with power cord detached to wherever you can get to.
Does it POST? Can you access SETTINGS?