Pc power off during boot up for higher cpu speed

[boydee12]

Hello, i have P4 3ghz s478 processor and it has been running for 3years not until today when my pc suddenly power-off during boot-up.However, when i tried to put my old P4 Celeron 2ghz processor into it, it work properly and no problem of such type was encountered...I bought p4 3.2 ghz(tested at store as good item) and i encountered the same problem again..Replaces it with P4 Cleleron 2ghz and my system work properly..What do you think is the problem?Need your advise...thanks

 

[unreal9400]

Clean the heatsink and fan.
Remove the old thermal compound on both CPU and heatsink.
Apply new thermal paste on CPU.
And make sure all the pins are in good condition.

 

[Cazalan]

The power supply is usually the first thing to go.
Especially cheap ones with low quality caps.