Computer parts can be come VERY hot and if they are not cooled down sufficiently it can ruin your computer. The fan is to cool down the processor.
It keeps your processor coo so it doesn't melt down. Its a very soft metal and it's very hot inside a computer.
to stop inefficient cooling
Processors themselves don't make any noise; it is the cooling fan. The noise a particular computer puts out can vary by model of processor, brand of cooling fan, size of cooling fan, and age of the cooling fan. As such, there is no definitive answer to your question.
To cool the processor
If you are moving your current processor into the upgraded motherboard, your current cooling fan does not need to be upgraded.
A computer fan is any fan inside, or attached to, a computer case used for active cooling. Hope its helps :)
The heat sink absorbs the heat from the processor and then the fan disperses the heat.
i'm assuming you mean your computer processor fan. If so, replace it. It's dead!
cool transmission
Assuming you meant 'cooling fan' - It simply to prevent the processor overheating. Modern processors perform tasks at high speeds - producing vast amounts of heat. The internal circuitry of a processor includes of microscopic strands of wire. If they're not cooled by a fan - the heat generated can actually melt the circuits of the chip !
The most likely reason is that the fan is on to cool your processor. The best way to tell is watch your system monitor. If the whine corresponds to when your processor is being used lots it is probably the fan cooling it off.
cooling the power supply circuity
The processor (CPU) is on the motherboard inside your computer. It's easy to spot it's location because theirs a fan above it cooling the massive heat sink that's glued with silicon to it.