My PC overheated ! 
I wonder why?
Most PC's have a  fan, at least one, to keep it cool.
If the fans is dead, the BIOS may not allow the PC to even turn on fully (black screened)
All PC' overheat if not kept clean. (even 1 year old)
Most Laptops laying on  blanket overheat
( if you see vents on the bottom do not block them ever)

All electronics parts (chips for sure and CAP's) do not like excess heat, too much heat and all fail, some chips get super hot and fail fast, the top 3 hot parts are , CPU, GPU and GLUE logic chips.
The CPU will shut itself down at 90C no harm, but shuts off,  the GPU may burn up not cooled properly , don't let it !
The CPU also slows down when too hot. (the slower clocking chip lowers heat greatly)
The 2 main processors, the CPU and GPU both can add up to 200 watts heat dissipation (TPD), full load (gaming?) the newer PCs draw way less power, at  the 2 chips for sure my GTX1050 is way less heat by 5 times less !)
  • The power (TPD, total power dissipation, or wasted heat) can be as low as 15watts and up to 100watts (CPU) + 360watts (GPU) for a total of 460 watts. (gaming or under huge engineering software, CAD/CAM/CAE or simulations)
  • The Power of the PC and the add-in  Video card are all covered in  there respective makers manual,  not reading the manuals is the big problem. (tossing a PC together?)
  • Not cleaning a PC with shop air or CAN-O-AIR every year is a big problem.
  • The BIOS in the PC will shut down the PC if the fans are dead, (mine screams the fans and is programmable this rate (a curve) ) The BIOS  as80C limit on the CPU temperature and if this hits, it will shut the PC down after fast fan runs.
  • I am not covering fanless PCs here, with heat spreaders and whatnot, nor watercooling systems, that Gamers love.

If the heat is not expelled to the room (space)  that the PC resides, then that chip overheats and can do so fast, some in seconds flat !
The CPU has over temp sensors "inside it" that cause the processor to slow down then shut down all by itself. (see here how this Intel magic happens)
The top failure modes are:
  1. All vents packed in lint. Clean them.
  2. Fans packed in lint and stalled. (2 or more fans on Desktops (real ATX desktops)
  3. Fans bad  (  or just its wire cable unplugged) Or on real desktops someone turn the fans off in BIOS, (a blunder)
  4. Heat radiator in the laptop blocked in lint ( common this)
  5. TIM failures (thermal interface materials)heat sink grease or even the heat sink fell off, in say shipping , drop damage. (seem it many a times on desktops) The best TIM is here.
  6. The room location with PC you are in is 120 F?  sorry that won't work, RTM you users manual told you not to do that. (put your server PC in a closet?)
 Some old laptops (2010) fail to stay cool unless you add and run a free application program that lets you turn the fans no full tilt, on my HP Elitebook i7 has a hot running processor (its the fastest one) and runs hot when I'm on the beach.
 By the same token my i5 laptop runs cool and never overheats, but it is very slow processor.  (my PC has over 10 CPU choices, some burn more heat TPD)

Covering Desktops (DT) and Laptop/Notebook/pads (LT)  (this is what we call a NO BRAIN'R)
The Cure is simple.
Laptops waste  up to 15-100watts power in heavy use, is the range running fast App's, this heat is all mostly inside and must escape, if not allowed to breath and escape, and vent  the hot air, parts inside over heat and fail or self shut down.
Gaming desktops PCs can use 2 times that power level and attendant more heat.
My gaming desktop Z270 I can set the fan speeds as  a curve (it has RPM and temps measured graph scaling adjuster) this allows me any fan  speed I want at any time)
( Blowing up a $300 CPU/GPU  is not good  ?) 
Heat is the number one killer of all electronics.!  (besides lightning and floods or you  dropped it 6 feet to concrete floor)
The ugly photo's below are all neglect. 
(even 1 year of neglect can pack a fan and faster with pets)

I will do a slide show now, to show how classic filth kills any  PC DEAD!

Most of the photos here are so captain obvious.
Vacuum it out first. (then use CAN-O-AIR  or 20psi max shop air to blow out the rest)   we use a line with a HVLP paint spray regulator to limit the force of the air pressure to safe levels. (100psi or more will damage parts inside)

Now examples show and tell:  (5years of neglect?)  Obvious !
we say RAT NASTY , at first glance.! (lint from rugs, hair balls etc)

More examples.
Desktops are so easy to clean , just 2 screws left cover off, and gentle vacuum it out first then go outdoors next, and the use CAN-O-AIR.
My HP Z600 has simple latch on the side , one finger and off the lid comes.
I can go to the garage, fire up the (SHOP AIR) compressor set the regulator to 20 PSI, and blow out a Desktop in 5min work.  I do so once a year. (less often now with my new hardwood floors!)

More Neglect:  (We vacuum first then blow) The blow out is done outdoors, so the lint lands in the yard.

Laptops (LT) are not easy (unless lucky)  to clean or service. but lets  do some now...
The laptop can be cured in many cases(no pun) not dis-assembling the complex case , by simply blowing out ALL vents clear of lint, and for sure the 1 exit vent , be sure to back blast it., with CAN-O-AIR.
In more extreme cases of overheating one must take the Laptop apart, no 2 laptops are the same (fun no?) you must read the service manual to dismantle any laptop,  HP and DELL have those manuals, many poor Asian named, PC none exist.
Buy HP  or DELL and win, do not buy the cheapest PC, if wise.
Some PCs the keyboard on laptops come of easy,  my HP has painted logo's markes on the bottom in the shape of  a keyboard, I unscrew those and then the keyboard is free, if  then yank the cables (ribbon) the connector on the mobo is broken.
A $300 big time error, do not work on any PC LT until you learn to work the 3 classes of ribbon connectors first or you will go broke fast. (sorry)"push on, hinge clamps and wedge clamps" are the 3 types, learn those skills first !

Below:  (got for free, dead, CCFL lamps DEAD)
Example Toshiba , not too old. 2008? 
The first thing to clean is A and B:
See this heat radiator, left end? "A" ARROW  below it must not be allowed to packup in lint.   (Back blast the port B now)
If the fan is dead, clean it first.
This will cure most fans from stalls. (for sure hair balls from pets , ouch)
See the FAN,at "B" ?  that fan must NOT be allowed to be packed in lint , in fact if you ignore the packup this will stall the fan and the CPU will shut it all down ! overheated,  "intel inside" did that, like magic"
The fact is most laptops makers (oem engineers) made them super hard to clean, that RADiator A , is super heard to clean, we remove the fan and then clean it out.

Removing just my keyboard or case top, helps greatly here to clean the fan and Radiator (RAD) seen here, (a Toshiba and is horrible to undo hidden plastic snaps, I hate Toshiba LT  , these was frebee, I'd never own one...ever.)
 I'm upgrading this one to LED screen for a friend. (the CCFL lamps died)
Laptops love to overheat way before any desktop. (due to that RADIATOR port being so small AND CONFINED , see marked A above.)
The same goes for all bottom vents below, if you run the PC on a blanket it will overheat, or if the vents on the bottom are all packed full of lint, it will overheat. 
See those 6 vents on my Great Quality HP laptop? below?, do not block them or allow them to pack in lint.
SOME LT, the keyboard has vents around its rim, that suck air.  (if blocked?, oops a daisy)
ALL computers make heat,  (just like your cars engine does) and you must allow it to keep itself cool (called thermal managment to an engineer) if not?, they all overeheat.

The Below is my Elitebook HP 8540W. See the vents,  keep them clean?

The HP 8540p/w series below the key board comes off with 4 screws , the screws on mine have cute white icons labels , for keyboard.
Every year, I  back blast the fan seen here to keep the radiator clear and clean.  (I blast it both ways at all  vents and on left then at fan port)  20PSI max if using shop air like me.
Back blasting works best with keyboard removed.  (let the dust cloud float down the drive way to the street)

Facts: The heat sink tops, Not the RAD or copper pipes run at 100F (38C)   (if say the hidden radiator on the left , is packed in lint then the heat sinks get way hotter and faster, and then the CPU shuts itself down.
Most if not ALL PCs have 2  shut  down BRAINS, All CPU's will self shut down, and in almost all cases, the BIOS Brain can too.  (goes slower then if unmanageable still, boom shuts down by DESIGN)
The GPU runs at 105f (41C)   if the fan fails or packs in lint or the RAD it will overheat real fast. (8540p) (IR thermal GUN READINGS BY ME)
The CPU shuts down at  about 90C, never let any CPU run anywhere near that. (the P4 and newer processors all HALT at 90C temp, you can not stop that, only fix the overheating cause)
A goal for any CPU is about  50
C max, some go to 55C, well away from 90c trip point , see?  If the fan works below and the RAD is not packed in lint, it will run cool or the TIM is bad.
One thing is if you remove all RAM the BIOS goes dead, and the fan too goes dead, so do not run it RAM free, for  more than  a few SECONDS.
 This LT has 4 RAM stricks. 2 top , 2 bottom.
Test RAM 1 stick at time. (testing for bad RAM)
The RAD can only be seen looking in the left side vent, it can be back blasted with air to clean it out, but the keyboard is best removed for the filth to land somewhere good like the back lawn or driveway, not inside case or home.

If you don't keep it clean like above, (annual)  you then  get to do this  horror.  taking the full top off, then remove 9 heat sink screws , clean it all on a bench the use this TIM  to put back all heatsinks or heat pipes
In most cases I never need to strip it down this much,  I use the air blower to blast it out 100% free of all lint outdoors.  Keyboard out , really helps greatly,  do not force those tiny connectors, learn now to deal  with them gently.
See this fan port, blasting CAN-O-AIR to the left side , can clean the RAD easy. Try that first, before  more extreme disassembly.
Some heat sinks , I discovered the TIM compound turned to hard fractured glue, the cure is this.
WARNINGS: (to non-tech's)

The laptop has tiny frail ribbon connectors there are 3 types, force on,  hinge type or wedge type.  (each type is a skill set all TECHS learn fast, or go broke $)
If you break one connector (not cable) , it's a $100 to $300 fix. (you get to buy a new Motherboard now)
If just  one cable is bad , you can buy them best place is Fleabay used.  Most PCs new parts sales end like in 3 years old,(yes, sucks)
If you fear damage, why not ask your PC shop to clean it for you. 
They know all about this  , I promise.
Best is not own a laptop at all , unless it's a throwaway Chromebook.
I you need no mobility get  nice desktop even  used Optiplex 990 is a very good PC, As are HP z600 used !
A Desktop is 10x more easy to clean, repair,diagnose and upgrade than any Laptop ever made.  A fact.
 Do not buy $1000 laptops,  buy $100 Chrome books. (or buy 10 Chromebooks and throw 1  away when it gets full of coffee spills)
If you game, get  play station or a real Desktop gaming system.( or build on using  a Z600 ) end rant on LT.

The cure for LINT: 
Can o Air. duster

Take it outdoors, and blow it clean  using shop air or CAN-O-AIR (duster) sold in all good stores.  (never exceed 20 PSI pressure)
(I do use a vacuum cleaner first,  on the worst cases, see far above , then SHOP AIR with the 20 PSI regulator inline...) NEVER BLAST using 150+PSI shop air, ever.
Then blow all heat sinks and fans clean.  (and annual event here) always do this outdoors, never inside...
 It will be a nasty cloud like PigPen(tm) cartoon character. (wear PPE,  gear while doing this, or risk eye damage) wear GOGGLES !
You want all filth to land OUTDOORS.

Intel proof of Processor CHIP DIE LEVEL protection: "Thermal Shut Down" ( it will slow down then HALT)
CPU: (the first time you will discover this is the first time the heat sink falls off.)
The Intel chips have this feature for many many generations, it's not a new features  at all.  (THE AMD processor does the same thing for the same reasons)
I believe Pentium 4s and newer all have this, for sure most PC still running well today do this, all do, mostly.
In FACT Intel CPU (and AMD) auto self shut down and HALT when too hot. (in seconds) Read page 36
From"Intel 64 and IA-32 Architectures Software Developers Manual Volume 3 (3A & 3B): System Programming Guide" at

Section 14.5.1 Catastrophic Shutdown Detector
P4 family processors introduced a thermal sensor that acts as a catastrophic shutdown detector.

This catastrophic shutdown detector was also implemented in   Pentium 4 ™, Intel Xeon™ and Pentium M™  processors. (relics of the past now but all processors have  today)

It is always enabled !

When processor core temperature reaches a factory preset level, (90-100c?) the sensor trips and processor execution is halted until after the next reset cycle.

This  mechanism is built-in to the processor. (self contained, there) Intel Inside ! ding ding!

But do know most BIOS BRAINS (code) have there own thermal controls and its own sensors and will speed up the fans or shut down the PC at 80C.  (independent of Intel magic above)

My old I-7 processor runs very hot, so I run a windows app that over-rides all fans, in fact when outdoors at the beach, (hot) I run the fans full tilt (max RPM) just to keep it cool. (2010 technology here)

There are pages like this, for every Intel CPU made, this one goes in to great depth, no more guessing.

Covered here too, on modern Intel,  CORE2™. (see all pages  on thermal protections)

Question of the day 1:
Why would Intel let you burn up any $300 t0 $500 processor? answer: they do all that is possible to protect  itself from permanent damage by you, or by bad luck.
Nor will let there CPU burn up. (By Design !)

All causes listed here:
(I will not cover missing parts, or sabotage of parts inside any PC) (example: a used PC and last guy left the heatlinks all loose and installed wrong! Dang!)

  1. A Filthy PC, as stated above. See the slide show above for more horror's.
  2. The vents are simply blocked in lint or other  materials, like any laptop sitting on a blanket.
  3. The CPU heat sink (HS) fell off the CPU, touch it gently feel it, is it loose, oops. (fix this now) Mostly this happens on desktops, even shipping damaged.
  4. The The PSU or the CPU fan is dead or all packed in lint. My Z600 work station has 7 fans inside, not counting PSU, and all spin slow and quiet , until I do wild things, like run a fast $60 GAME.
  5. The Desktop GPU fan is dead., or case fans are dead. (a.k.a. the graphics card with a fan, all faster cards use a fan. Mostly for Gaming or CAD work. video editing /rendering, etc )
  6. The TIM failed,   (TIM = thermal interface material) or Heat Sink Grease (or compounds) , see my short page here.  We use only SHIN ETSU grease.  
  7. The Laptop  Radiator is packed , see it here. This is where all heat goes to this cooper radiator, and air must blow out the fan then pass through the RAD and exit the PC or it will overheat.
The heat Radiator device.
Are not photos great?, clear as bloody day what is wrong here,  NEGLECT, not servicing any PC of any kind , invites this problem.
That copper pipe has a wick inside the copper/methanol/alcohol working fluid coolant inside, works like the pumplesss refrigerator seen in mobile homes (kinda)
 The Coolant flows by convection current principles. Takes the heat off the top of the processors and lands on that RAD.
The problem in some case for sure hairballs,  the back blasting with air fail to get it clean.

One more FUZZ monster, this poor guy run the PC for 5 years never cleaning (2008 HP) and overheat the GPU and the GPU was distroyed.

end of filth.

I refuse to cover water cooled PCs, nor fanless PC's or tablets. (all are very high end $$ and complex thermal designs)
nor fake Desktops like this thing! (so called "All-In-One" PC's)

Jargon: 101
CPU, the central processor unit chip, see here.
GPU, graphics processor chip,see above link. (my GTX Nvidia cards all have fans)
MOBO the mother board seen here,  or seen here.
TIM , heat sink grease.(thermal Interfact material)
Heat sink (HS), this is  huge finned block of aluminum in  Desktop, (mine has 4) and the fins radiate heat, the purpose of the HS, is to move the heat from the CHIP to the AIR stream.
RAD is Radiator this is only seen on laptops,with a fan and thermal heat pipes,  These pipe flow heat to the RAD and then the fan blows it out of the confines of the Case to the world. (heats your room it does) even as much as 100watts heat.
PSU, power supply unit.(it too has a fan and must not be DEAD)

What is a Heat Sink and why  do we have them.?
The Heat-Sink (or HS) is metal device, that fits on top of all very hot running chips (even hot power transistors have them and VRM)
 That cool a chip that expels say 100 watts of heat ,ever touch a 100 Watt light bulb and get burned?  100watts is not  tiny! OK?
Most chips only get hot under full load, like the  engine does in your car. (like gaming in a PC)
See your dog pant?, that is his tongue, that tongue is a heat sink and cooling device. (a dog can not sweat like us humans, so pants)
The PC must not harbor heat inside the case or the heat builds up, and if this happens things fail.
The heating captures the heat first using TIM,  and after a good capture, it then conducts heat (copper is best , aluminum 2nd) and sends by thermal conduction this heat to 4 possible places.
  1. To local fins that transfer heat to the air inside a PC and then fans in the case carry said heat out of the case. see the CPU fan below.
  2. To  heat pipes, to a radiator device and then to the air (outside the case)
  3. or to a water cooling system that gamers use.. (then the water cooler radiator device then expels all heat )
  4. Or as Tablets do some have a huge heat spreaders, that transfer heat directly to the case and the case then gets warm and is air cooled outside the case.
The hot chips must be be cooled in some way or the chips will be damaged (CPU is the hardest to damage ,as it simple slows and shuts down saving its bacon)
The 2 bridge chips can run hot too,  South or North, some are 25watts of heat each.
These chips are mostly with fins or metal spreaders as see below (only).
The goal in all cases is to extract the hot chips wasted heat (TPD)to the room you are in or to out doors if that is where you are now.
If you think this is hard to undersand try spacecraft !

HS or heat sinks. (they first sink the heat (capture) and then transfer it else where to fins or large plates , or to heat sink pipes and to a radiator device that expels heat out of the case.)
Glue logic  chips not CPU, not GPU ,   called the North bridge and  South bridges, they too must not overheat, my x38 chip runs hot and it too has  a heat sink. (that must have cool air available)
 Some of these Glue Logic chips  heat sinks on them I have seen them fall off too. ( some are clamped on others glued on (thermal epoxy) the former can fail easy. (including bail wire clips and plastic funky riveted HS)
Show and tell:
The fast i7 CPU below is cooled by the intel heatsink and fan. You cans see the aluminum fins clearly , and
91 watts TPD. (fully loaded watts)!
The cute heatsink top left is for the VRM transistor cooling.
The lower right  heatsink is the SouthBridge Intel Z270 expels only 6 watts TPD. The best mobo I  have ever owned, and the fan ticks over at at 415 RPM as I type this.

Three cheers to the maker of great motherboards from 1995 to now.

version 10.  7-25-2017  (covering topic, "taking out the TRASH"), by: DeadPool  ,revised  7-1-2018