David, perhaps you can solve your issue in your own thread. I don't think this is germane to the OP's problem and this is going way off topic.
I replaced the PSU and it still shuts off and restarts next task try another Graphics card and also to play safe change the AMD CPU cooler and replace thermal paste,also thought about reinstalling windows 10 on a cleaned drive.
@martinlw I just had a graphics card start causing shut down issues recently. The computer would randomly reboot even without load. I thought it was the power supply or the MB. I had a decent older card lying around so I decided to install it. The computer boots normally and it doesn't reboot on it's own anymore. I would see if you can get a hold of a GPU (old one or a friends) to see if it is the GPU. Cause at current GPU prices, you don't want to replace it if you don't have to.
I forget, did you reseat RAM and run memtest86 overnight yet?