well the other day my pc died. failed to acknowledge that i had a HD. so i thought HD failure. tryed to boot up this arvo just to be sure and it worked! the pc had been running for like 5 days straight before the failure so id say it overheated.
THE MORAL OF THE STORY
fortune cookie says: when jackie chan movies you are downloading, a fast tracker you must do it with.
after a PC has been running for a couple of hours it is as hot as it is going to get
“If overheat it is you suspect, fan condition you must check.”
If your fan’s dying, the rest of your PC can fry if you don’t replace it in time.
Also your problem could have been as simple as a loose plug or something, and then you went all miracle on us. 
get you self one o dese
One of my friends built his own computer and to cool it he has this bucket of water with a pump and a plastic tube running all the way through the computer and back into the bucket.
I hope he also has a rad or something in the loop. Otherwise he would be a terrible liquid cooling enthusiast.
well i hadnt touched the connections before it died. but i did before it worked.
Also in checking the fan, check the CPU heat sink. In some environments a build up of fan blown dust can accumulate on the cooling vanes, act an an insulator, and negate much of the cooling effect of the fan.
Nao
Yes, pump beer through your computer! 
my case has like 3-5 fans and ia usually well below the target temp. it hovers around 30-40 degrees celcius. i do want to put a car radiator on the side tho. but i have no time. im already making a cnc mill and fixing a car so im pretty busy.
and for the dude with the liquid cooling, you live in canada, shouldnt you have a heator in it instead:)
but i have had my pc not start cause it was too cold, many canadians have aswell.
that is the proper way to do cooling! kinda peeves me off seeing these people with too much time and/or money putting ridiculously over sized heat exchangers and fat hoses on things. if you want to go all hardcore with the cooling then put the bucket of water in a beer fridge with a little hole in the door for the water hoses to go in and out.
having said that, if you are ok with your kit running at 40 deg C (which it is designed to do) then use air and a fan!
My computer kept suddenly turning off at seemingly random periods. Eventually it stopped working all together. Turns out it was the cpu fan knackered. It had stopped working as well as it should have done, so when I tried to do anything remotely strenuous it would turn itself off because the cpu was overheating. Eventually it killed the processor completely.
Expensive mistake there! If only I had realised and spend £5 on a cooling fan, I could have saved myself £60!
Edd
Because a beer fridge really has the capacity to deal with a constant heat load like a modern computer. 
For the record: my computer is liquid cooled in a similar way to Borgschulze’s (only I used more duct tape).
Reasons liquid cooling is better than a simple heat sink and fan system:
-huge cooling capacity: using a reasonably sized car heater core as a radiator you can cool a CPU and your GPU (and chipset…) and still get lower temperatures than a traditional air cooling setup.
-it’s pretty badass
Practical example: I’ve got a heavily overvolted Core 2 Duo @ 3.5+GHz and an 8800 GTS @ 700+MHz (core speed) and my temps only ever reach 45 C under the heaviest loads when the room temp is high to begin with.
Depends on what you’re running. The temps of the CPU and GPU will fluctuate in response to the amount of work they’re doing. An idle CPU will only get so hot… until you run a computation-intensive application, at which point it’ll heat up even further.
A sure way to get your GPU temp up is to start up an FPS such as Half-Life 2 or GTA III in 1080p resolution. Better have plenty of airflow for that!
I had the same problem, but in my case the heat sink wasn’t properly secured to the CPU. Everything looked good, but the connection wasn’t tight, or not enough thermal grease was used, so the CPU overheated anytime I ran several apps at once. It was maddening to diagnose and expensive to repair… but now I know better! 
Depends on the quality of the PSU. Some PSUs have temperature alarms and overtemp protection (i.e. thermal fuses).
You can get passive PSU’s, and even watercooled PSU’s.
If you buy a half decent PSU, you won’t have a problem with the fan dying.
Do you seriously trust hundreds of dollars of equipment to be run from a $20 power source?
By the way, voltage can’t kill you, amperage does.
EDIT: My power supply clearly sits in the bottom of the case, with far less heat load to cope with, therefore extending it’s life, while reducing the noise of the fans.
Actually, incorrect usage of apostrophes kills
No, seriously, it’s power that kills.
Counterexample: an automotive battery can produce hundreds of amps for a sustained period, but one doesn’t die simply from touching the contacts.
The human body offers a large amount of resistance (on the order of millions of ohms) to electricity… so in order for a power source to send electricity through the body it must provide a significant amount of EMF.
Voltage or amperage alone are not enough to determine the hazard of a given source… once you consider the impedance of both the power source and the sink, then you’ll understand… power kills.
Go, twit yourself, twittish twitter, of doom.
I was at least partially correct.
