Laptop crashes without a BSOD for no reason

[Boops De Dooper]

Odd problem I'm having here. When using my laptop, it crashes without a bsod. Just the buzzing of the speakers and the screen freezes and I have to force restart. Nirsoft bsod viewer doesn't show there being any crash dumps.
The crash happens at any time really. It just happened while watching youtube and didn't crash while gaming earlier.
No software or hardware changes were made recently.

CPU: i7-5500u
GPU: Nvidia 840M
iGPU: Intel 5500
OS: Windows 8.1
Browser: Opera 55.0

 

[t53186]

Can you monitor your temps, like CPU, could be a thermal shutdown. This program will help confirm your temps. https/www.cpuid.com/softwares/hwmonitor.html
Or use event viewer to look in the system log for a error

 

[Boops De Dooper]

I monitor the temps with Speedfan and while Temp1 is reaching 85C and GPU is around 70C, it never shuts off, just thermal throttles. Event viewer has a critical error "Kernel-Power" error and an error saying the previous shutdown was unexpected, likely because I force restarted. But that's about it.