Question PC shuts down randomly not even playing a video game

[Greg Gregorich]

hi all.i have situation where my pc randomly restarts even pc idling.my case fans is a mesh .its supposed get throttle first but now its just shuts down and restarts what i did used extension for my gpu to move outside the case and i put fan under it installed liquid cooled by h100i elite capellix xt .once i cant even make Battlefield 4 to launch its shuts pc down after i click find a server.then i tried reset my pc and now its sometimes background gets black .no background picture lol.its just too much.thanks all

 

[Greg Gregorich]

Motherboard: ROG MAXIMUS X HERO
CPU: i7-8700k
GPU: GEFORCE RTX 2080 TI
RAM: G.SKILL TRIDENTZ @ 2133 MHz
PSU: EVGA 850 T2
Storage 1: 500GB pci 3.0 NVMe SSD dont remember brand .
Storage 2: CRUCIAL 2TB M.2 NVMe SSD in enclosure connected via usb type C with COD MW3 installed.
OS: Windows 10 Pro