Question PC Random Hard Hang issue

[willie030]

Oooooooooookay... so I have been trying to find out why my computer is crashing, what could be the issue...

The following is happening:
List of specs:
Operating System
Windows 10 Home 64-bit

CPU
Intel Core i7 4790K @ 4.00GHz 33 °C Haswell 22nm Technology

RAM
16,0GB Dual-Channel DDR3 @ 799MHz (11-11-11-28)(Overclocked settings are different)

Motherboard
ASUSTeK COMPUTER INC. MAXIMUS VII RANGER (SOCKET 1150) 24 °C

Graphics
DELL ST2310 (1920x1080@60Hz)(Monitor) 4095MB NVIDIA GeForce GTX 970 (Gigabyte) 25 °C

Storage
223GB KINGSTON SH103S3240G (SATA-3 (SSD)) 22 °C 1863GB Seagate ST2000DX001-1CM164 (SATA ) 25 °C

Optical Drives (CD-Disk mounter)
HL-DT-ST DVDRAM GH24NSB0

Audio
NVIDIA High Definition Audio

Here's my issue: my computer randomly hard-hangs after playing CSGO for a while. Sometimes it's after 20 minutes, sometimes after 3 hours. I also got this once whilst playing DayZ. I checked the CPU and GPU temperatures and they are fine (I recently reapplied thermal paste to the CPU). I also cleaned the GPU fans for any dust. However, it still gives me the hard hang. There are a couple of things that are noteworthy here:

1. The error ONLY OCCURS when gaming. It doesnt happen on a game like Combat Arms (Classic), but it DOES happen on CSGO (its like two in three games the PC completely crashes) and after about 1 hour of playing DayZ.
2. I checked for CPU and GPU driver issues but windows-update and the nvidia page both conclude I have the most up to date drivers.
3. I am not sure how to check RAM or my HDD/SDD.
4. When I bought my computer it was overclocked in some way (I don't completely understand why, and what was done) but I reset my bios settings to factory default in an attempt to fix the problem.
5. Windows logs don't provide any interesting information.
6. When the hard hang occurs, the entire PC freezes up to a point where I have to use the on/off button to restart. It randomly hits and when it does, the screen freezes, sound freezes (it still plays like the last second of moving sound like it's stuck with the screen), and the keyboard and mouse are, logically, unresponsive (caps lock doesnt work).
7. I scanned for virusses: clean. I scanned and cleaned with CC Cleaner, so: clean.
8. I used FurMark to sort of test the GPU and the CPU again... no results though. It didn't cause the hang!
9. I reset my windows with a factory reset and reupdated, still didnt fix the problem.

SO: if anyone can help me with my issue: please! PLEASE! it's annoying and i'm afraid the hard-hang will occur when i'm actually doing something serious...!

 

[rgd1101]

brand and model of the psu?

 

[willie030]

brand and model of the psu?

Cooler Master G750M