PC Randomly Crashes, Audio Repeats

[Kopmeister]

This admittedly has been happening for a while but I initially pinned it down to intense usage (during Battlefield 1) however now it's starting to occur seemingly at random (although never at the desktop, occurs whilst playing videos for example), regardless of the intensity of usage on the PC. Due to it being random, there isn't any way to trigger it for troubleshooting purposes. 

The PC will just freeze up and the audio will repeat, needing a force restart to be usable. Having performed Windows Memory Diagnostic, FurMark and Aida64 tests the results come back okay with no thermal issues. Drivers have been checked and are up to date.

System specs are as follow:
OS: Windows 10 Pro
Mobo: ASRock H170M-ITX
CPU: i5 6600 (non K)
GPU: ASUS R9 380 (4 GB)
RAM: 2x4GB G.Skill Ripjaws V 

PSU: CoolerMaster GM550W
Storage: Samsung 850 EVO 250GB and Seagate Barracuda 1TB

Thanks!