If it is a HP or Dell, most of the time with the HPs the thermal grease between the heatsink and CPU gets dried out. you have to remove the motherboard and remove the old thermal compound and apply a new one and put everything back together.
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Most of the time with older laptops the thermal grease between the heatsink and CPU gets dried out. you have to remove the motherboard and remove the old thermal compound and apply a new one and put everything back together. This is IF the fan is working properly, sometimes you will also get a lot of dirt on the heatsink you want to blow this out with compressed air since you have everything apart anyway.
If it is a HP or Dell, most of the time with the HPs the thermal grease between the heatsink and CPU gets dried out. you have to remove the motherboard and remove the old thermal compound and apply a new one and put everything back together.