Hi Andrik11
This one is hard to put a finger on, so I'll try a little checklist of possibilities:
The software possibilities start at the video driver since that's what seems to stop working first. I suggest uninstalling the video driver and re-installing it, possibly with an update if it's not the latest. (You have an nvidia card, but those symptoms are close to a recent AMD driver bug.)
The other possibilities are in BIOS. The suggestion is to save any OC profile, then revert to defaults.
Re-flashing ver. 2012 might fix a messed up flash.
You could also revert to an older BIOS unless there's some feature in 2012 that you need.
A case cable could be causing power-off or reset signals. To check, unplug the that cable from the motherboard temporarily and use the on-board power switch.
CPU socket pins are on the checklist for any mysterious failure. The suggestion is to take out the CPU, inspect the socket for bent pins, then re-install the CPU. What CPU cooler? What TIM? Use care to tighten the cooler evenly and not too tight.
While 650W is ample power for the rig, there might be an intermittent failure dropping power suddenly. Try plugging into a different mains socket. If it is possible, try a different PSU for a while. This may be the most likely fix, but also the most expensive. I suggest trying the other things first.
A little more involved is the one-at-a-time approach to troubleshooting the hardware components.
Try one RAM stick at a time, perhaps try it in different sockets.
Remove the video card and use the 4790K integrated graphics for a while.
What storage devices? Try reducing disks to just the boot device.
Another possibility is that a crash or some other thing damaged Windows and set it up for these Kernel errors. You could try a repair from the Windows installation media or even a fresh re-install.
Hope something here helps.
Jeff