Question PC power cycling - not sure what is wrong!

May 21, 2020
Hi all! I'm having trouble with my 6 year old computer, which has been working without problems since recently. Starting about a month ago, the screen would randomly go black, the fans ramp up, and then after a bit it would turn off. Since I could turn it on again, I didn't do anything . However just recently I haven't been able to turn it on - it would just power cycle (a few seconds on, turn off for a few seconds, and repeat - all before anything showing on screen). I tried to diagnose it:
I bought an extra power supply. I've taken out the CMOS battery and retried. Now I've taken the mobo out of the case, and with only the CPU and CPU fan, I can get it to stay on and I hear the beep codes. When I put in a stick of ram and turn it on, it would go back to power cycling. This would be regardless of which of the 2 sticks of ram I try, and regardless of which ram slot I try. I don't hear any beep codes when the ram is inserted.

I am considering taking out the CPU and checking if there might be anything wrong under there, but otherwise I am maybe considering on just getting a new mobo.

Anyone have any thoughts? The current mobo is an ASUS Z97-A paired with an
i7-4770k cpu. There doesn't appear to be any obvious damage on the mobo. Thanks in advance!