I really don't want to get involved in this topic, there are already enough people involved whom I believe have the knowledge and expertise to solve this problem. However, way back at #2 ScathEnfys said -
Is this a laptop or desktop? Have you taken it apart to deep-clean any dust out?
Make and model is fairly basic information which should be included in every topic ! Is it a desktop or a laptop ? And, from #14
I did clean the computer.
What did this involve ? Merely blowing / brushing out dust or did you remove the heatsink assembly from the CPU or disturb the heat pipe if a laptop ?
If you did either of these latter actions it is not sufficent to just screw or clip these assemblies back together. The mating surfaces need to be thoroughly cleaned with something like methyl or iso-propyl alchohol and finished with absorbent paper, and then you need to apply a thin layer of heat sink compound or paste (same stuff, different names) to one of the mating faces before reassembly.
If you split the heat sinking surfaces then new heatsink paste is essential. It's widely available and reasonably cheap.
Chris Cosgrove