The CPU temperature is very high.

Judging from the phenomenon of your computer, it should be a CPU heat dissipation problem, but if you install such a good radiator, it should be no problem under normal conditions. It is very likely that your cooling fan seat is installed backwards (INTEL 775, 1 156 will have this problem), and the inductor on the motherboard lifts the cooling fan, resulting in the cooling fan seat not fully contacting the CPU. I bought a 775-seat dual-core computer in Computer City some time ago. At that time, the weather was still cool, and the computer occasionally crashed. It is normal to check the fan speed with everest, and then check all parts with replacement method. This is completely normal and puzzling. Finally, the fan seat was removed, and this problem was discovered. It is very likely that JS did this on purpose, because it was cold at that time.