My pc keeps shuting down just after a few minutes I was using it, says our client. He has been using the pc for 2 years when it started making heavy noises about a week ago. Based on his explaination the possible reason for the heavy noise could be due to the CPU fan not functioning at its normal speed. A closer look in the system case reveals  that the machine needs to be service to remove the dust which have clogged the cpu fan, power supply , graphic card and other components.

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As you can see above the cpu fan is clogged with dust preventing heat dissipating  from the microprocessor  to the cpu fan. The processor eventually becomes very hot and in this case the user might experience system slow down or hang at the initial stages before it gets serious causing the pc to shut down automatically.

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You can use compressed air can or anti-static vacum cleaner to remove the dust, as for me a simple paint brush will just do the trick. While you are at it you might as well take the liberty to go through all the important components that needs cleaning such as your graphic card (shown below in Pic 5).

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After you have done with the cleaning, you need to inspect the surface of your processor to see if there is enough thermal compound, as you can see in Pic 6 the thermal compound has already dry out, so you need add in a fresh one which you can get it at just about any electronics or computer store. Becareful as to remove the processor before applying the thermal as they might get into other components of the board.

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I would recommend the white silicone compound because it is nonconductive and like the silver, which has metal in it and if it is not applied properly they can get into your motherboard connections and short it out. Just apply a thin layer of this thermal paste  onto the surface of the processor that comes into contact with the heat sink, this will increase the contact surface area between the processor and the heat sink, thus improving heat transfer from the processor. 

Finally fit in your processor into its socket and clip in the cpu fan to ensure its holding the processor firmly. Turn on your machine and it should be working just fine.