(Help!!) PC Randomly Restarts

Amzad_01

Prominent
Feb 16, 2017
4
0
510
Hello! I built this PC myself a few months ago, it runs perfectly fine but it has one issue, that being it restarts at the most random of times without any warning. I can't seem to find why or how after hours and hours of research so I thought I'd ask the community. First, some specs:

Windows 10 64 bit Pro
AMD FX-6300 (non-overclocked)
ZOTAC GTX 970 (non-overclocked)
GIGABYTE GA-78LMT-USB3 rev 6.0 motherboard
TOSHIBA HDWD110 1TB HDD
2x4GB DDR3 Corsair Vengance
600W EVGA Silver rated PSU
Coolermaster CPU cooler (forgot the name but its a tower cooler and very effective)
3 Case fans

Now, the restarts. I've deduced it is definitely not due to overheating. This PC can go on mining crypto for over 40 hours without any restart or slowdown, once it reaches the 50 hour mark it restarts I assume due to overheating. I can game for hours without issue and do everything you'd normally do. However sometimes when browsing chrome, or hovering around in League of Legend's menus, or discord, it restarts. The PC won't be warm, no prompt or popup but it'll just restart itself. I can't for the life of me figure out why. It's entirely random as to when it decides to happen, I can go for a week without any restart and then get 2 in one day somehow. The most recent restart was around 30 mins ago, I left my PC idle mining crypto for around 3 hours. Came back and opened up chrome, went on a website and it restarted. I honestly don't know what to do so any help would be very appreciated. This system was just built 2-3 months ago.

Many thanks for your time!