I NEED HELP! RANDOM SHUTDOWNS

[Traycasher]

I just recently bought a new power supply(EVGA Supernova 750 B2). It has been working great with no issues I also just bought a new 2TB WD Black drive for a total of 4TB of the same 2 drives I also just recently bought a new SSD but that wouldnt effect power at all. And i also have an old 80GB hitachi drive just in the background. MY issue is that when being lightly used or left idle the monitor will go black with the backlight left on and my keyboard freezes and I have to restart my computer. This may happen 2 times in an hour or 1 time in 5 hours. it  never happens when im gaming EVER thankfully but it will happen quite often while im using chrome or looking at steam. the Event viewer says unexpected loos of power. but my power supply was working fine this only recently started happening when i bought a new desk and plugged it into a surge protector that was pretty shitty. So I plugged it back into the wall and it still does it I am very confused please help. My System Specs are as follows:

 

Intel Core i7-4790K @ 4.0GHZ

ASUS 797-K MOBO

16GB Kingston HyperX Beast RAM @ 2400MHz

ASUS AMD Radeon R7-360 OC

2x 2TB WD black drives

250GB Samsung 850 EVO SSD

EVGA Supernova 750 B2 PSU

NZXT Source 530 chassis

Corsair K95 RGB Keyboard

Logitech G602

[paradigm249]

try a different PSU, maybe it can make a difference, just unplug so you arent using more than it can handle

[Traycasher]

I wanna try to move away from getting another PSU thats the thing but yes i will eventually if i cant fix it.

[ConnerArkell]

It could be a dying stick of RAM. even if it's brand new it happens

[Traycasher]

but why would it only happen during light use

[Shiwoon]

Explain lightly used? Like watching a movie/video? or Browsing the web?

[Traycasher]

like using google chrome and watching youtube yes