Why does my PC Crash? Reason 3 of 7 part 2
Heat is thy enemy
If everything looks good with your airflow but the temperatures continue to rise, check your BIOS settings. If you’ve messed around with voltage settings during some kind of overclocking escapade, reset the values to their defaults. The more voltage a component receives, the hotter it becomes.
If you have recently installed a new CPU, the crashing could stem from a poor application of thermal paste. So remove your heatsink, clean your surfaces with a cotton ball and a little rubbing alcohol, and try again.
There are competing theories on how to apply thermal paste, but your goal is always the same. The thermal compound fills the microscopic valleys on the surfaces of the CPU and heatsink to provide the most even and full contact between the two components. The paste is ineffective when too little—or too much—is applied. So I use the pea-drop method: I place a small, pea-size drop in the middle of the CPU, and then place the heatsink directly on top, letting the natural pressure of the heatsink spread the paste evenly.