PC shut down randomly and won’t boot for more than 5 secs

Since the last 2 weeks my PC has been shutting down randomly, with no blue screens or anything. Mobo light is still on. The last time I made any major component changes was about a year ago and it’s been working fine up until now.

When it does shutdown, I have to leave the pc for some time and then it’ll boot back up again, albeit not for long before it shuts down again. During this short window I monitored the CPU and GPU temps, which were both normal. Upon checking the event viewer it showed ‘kernel power error’ - which led me to believe the issue might be the power supply. I’m running the latest drivers and windows updates as well.

I just installed a new msi 850w power supply a few days ago and my pc was working great again, but this morning whilst I was using ZBRUSH- a sculpting software, the issue happened again. Now when I try to reboot, the pc turns off after 5 secs. Could it be the software that was the catalyst for this? As the first time it happened I was also working in ZBRUSH. If it’s not the power supply or the software I think that’d mean another component’s responsible?Any help would be appreciated, as I use my rig for freelance work and want to get this resolved asap.

Cheers, Dave