I see this is your second posting. Good for you in adding the additional information.
This may be rather lengthy genevacotton, so grab something to drink, and sit back.
The cooling system for a desktop computer consists of air flow through the computer case.
Air is brought in from the Front towards the Back of the computer. (Or for some gamer computers, through the top, or side, and out of the back)
Air helps to cool the hardware components inside the computer.
A Processor is one of the two main components to develop the most heat.
[ Below shows a typical Intel Pentium 4 processor. Operates at a maximum frequency rate, ('Speed') of 3.0GigaHertz,http://www.cpu-world.com/CPUs/Pentium_4/Intel-Pentium%204%203.0%20GHz%20-%20RK80546PG0801M%20%28BX80546PG3000E%29.html
Under the bold black heading > Intel Pentium 4 3.0GHz RK80546PG0801M ( BX80546PG3000E),
look at the tabs >
Specifications, Pictures (3), CPU ID, and Comments (0)
Click on > Pictures (5)
You can click on any of the photos to enlarge.
The photos show the top view of a Processor.
The silvery looking square case in the middle is the Processor chipset.
The Green square surrounding it is a circuit board.
Click on the third photo down. The one under 2008-10-05 14:56:45
Holding that circuit board up off of that flat black surface, are pins. These you do not see in the photo.
For this particular Intel Pentium 4, there are 478 pins.
This Processor fits in a Socket 478 processor socket.http://en.wikipedia.org/wiki/Socket_478
The photo shows the top of the Processor's case, with No Heatsink sitting on it.
This is a typical Heatsink/Fan combo,http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=262455&CatId=493
The Heatsink is the aluminum looking square object under the fan.
Your particular desktop computer may not use a fan on top of the Heatsink.
It may have a Fan in the front which draws air through a plastic tuned port.
The plastic tuned port in turn, then goes over the Heatsink sitting on top of the Processor.
Case in point with all of the above prattle?
The Thermal Paste used in-between the top of the Processor's case, and the bottom of the Heatsink, has dried up.
The top of a Processor's case, and the bottom of a Heatsink, are not perfectly smooth.
A microscopic view would reveal 'Pits, Hills, and Valleys'.
When the two surfaces of the Heatsink's bottom, and the Processor's top are put together, the before mentioned imperfections create Air Pockets.
AIR is an Insulator. Not a Conductor.
Thermal Paste is a Conductor. It conducts heat from the top of the Processor's case to the bottom of the Heatsink. and fills in the imperfections.
When thermal paste dries up it looses it's conducive properties.
The fans are designed to spin at an RPM, (Revolutions Per Minute), that is in compliance with the needed cooling for the Processor.
Processor isn't running very hard, fan/s spin at normal speed, (RPM)
Processor is running hard from multiple programs running, or intense games, the Processor heats up, and the fan/s spin faster.
Whenever the Processor heats up past it's thermal limit, (Maximum operating temperature), the fan/s spin faster.
If the Thermal Paste is dried up, the Heatsink, and Fan cannot cool the Processor properly.
The signal is given to the fan/s to speed up, but they still cannot cool the Processor.
The Processor overheats, and shuts off. The fans still spin at max RPM.
No computer operating, fan/s spinning at high RPM.