Computer shuts down during startup? Recently got a new computer. When I power on it starts and after 3 sec (WHILE STILL BOOTING -NOT REACHED WINDOWS YET) it shuts down and then restarts???? Why would this happen. 750 watt PSU and P8z68 motherboard. All new? Whats the problem? Hi everyone, I found out why my pc was booting twice on startup. I recently bought me a new cpu i7 2600k. It comes with a software program that enables you to overclock the cpu by 30% to a 4.5 ghz. When i overclock it happens. When I turn the pc on it turns on for about 3 sec, turns completely off for 3 sec and turns back on. It never tells me the pc wasn't switched off properly or gives me any errors. Is this a safety precaution? can it harm my motherboard? I uninstalled the program again and it works fine now. Does this mean I cannot overclock my cpu?