Unless your PSU became unexplainably defective, its something else.
Disconnect PSU from power - Perform a battery pull (replace and retest)
That's a lot of RAM.. Is it on the QVL from your board? Have you tried starting with just 2 DIMMs installed?
Do you have ANY other cards installed on the machine?
Please remove and reseat your memory
Confirm all electrical connections (reseat all)
12v CPU, 24 Pin main power, CPU fan to CPU_FAN header
retest
Still failing
Check your CPU socket
Remove and check for bent PINs
Reseat CPU, Fan and retest
Please report your results, progress