What's killing mobo

Edgecrusher72

Commendable
Dec 19, 2016
2
0
1,510
Ive got a socket am3+ and an amd 9590. Liquid cooled, no overclocking, 32 g kingston ddr3 and gtx970 graphic card. Ran great for 13 months then would no longer boot. If I unplugged psu and tried again it would POST then shut down. When turned on again just psu fires up but nothing else and will not shut off with power button on front panel or on mobo. Have to shut off at psu. I tested psu with a multimeter and is good.tested graphic card in a friends computer and is good. Tried to boot with only 1 dimm at a time and no change. So I deduced that the mobo was bad. I RMAed the mobo and bought a new one while waiting for old to be returned. Installed new mobo, worked great for 6 days now doing same thing again. What is killing my motherboards?