PC not turning on. Mb probable culprit

Hey guys

My specs:
Asus Maximus VIII Hero
6700K
Zalman CNPS 9900Max
2x G Skill Ripjaws V 8Gb 3000Mhz
Gigabyte G1 GTX 1070 Gaming
XFX XTR 750

So my problem:

In the past weeks my Pc just wont turn on after I turn it off for some reason.
Usually after a while I can turn it on again. But now I just can turn it on again.
Here are the symptoms:
-Start, Reset and Clear CMOS buttons on the Mb stay ON
-Asus Aura Led on the Mb stay on and cycling through colors as usual
-Pressing the power button on case or pressing the Start button on Mb does nothing

Last night after not using my PC for a while the screen saver turned on and after 30min the monitor shuts off. Normal. But when I moved the mouse it just said no signal, although I understood my pc was working normally when I moved my mouse. Pressed the power button and it shut off. Also normal. (Not a forced shut down, just a normal shutdown).

Today I tried to turn it on and it started apparently normal but without monitor signal.
tried to reseat my gpu just in case and now it just does nothing. Press power button and it does nothing.

Tried clearing CMOS by removing battery. Turned on for 2 secs and off again.
Tried clearing CMOS using the Mb button. When pressed, the Mb leds change. As soon as I release it, goes back to the same state.
Tried flashing Bios using a usb stick and just power cord. Apparently successfull. Pressed power button. Again turned on for 2 secs and turned off.

Tried reseating Ram and starting with cpu graphics: no change.
Checked all cables and connections.
The Mb has power because the leds light up and already turned on for a couple of secons a couple of times.

Ideas?
 
Update:

Tried flashing BIOS again to another version. turned on for a while. No imput to monitor.
While On the Q code goes through a lot of numbers, stops on code "01" and shuts down. afterwards couldnt turn it on again.

Checked what Code "01" is:

"Power on. Reset type detection (soft/hard)"

No idea what it means..
 
How old is the power supply?

clrCMOS by button, but remove power plug from the wall before and press power while off. Only then press the cmos button for about 5seconds. After this replug the power and try turning on.

try booting only with one RAM (move stick over all Dimm slots)
try running without HDD/SSD

 
Just did that, powered on for a few seconds, running several numbers on the Q Leds and stopped again on code "01". stayed there for a few seconds and shut down. At no time was any image on the monitor.
Pressing the power button afterwards does nothing.
 


Yes I did. But I'm going to test the psu on another pc first, although I doubt the psu is the problem.