This looks like an iffy PSU given those reviews. Talk to your PC's maker about swapping it a slightly bigger PSU (keep it single rail) and ask them to test the PC before return.
I am having a weird occurrence with the boot up of my PC. When I first hit the power button, my LG monitor appears as "HDMI Power Saving Mode" and does not display anything. What I typically do is hold down the power button until it shuts down (I know this is not ideal) and when I press the power again, the screen then appears with the windows loading screen. I have ensured this is not a faulty monitor as I have plugged in my PS4 and that works with no issues.
Just a quick reference to my build:
WD Blue 1 TB HDD
8 GB Crucial Ram
AMD 6300 Vishera
AS Rock 970M
Raidmax 535 Power Supply
GE Force GTX 750 TI