Fan Speed - Cause of Overheating?

Why don't you download apps to determine what the problem is.
Realtemp and/or Coretemp will tell you the cpu temp.
HW monitor will also provide more info about your other components and fan speeds.
These apps are free.
If you have temps over 70C on your cpu you've got issues.

Clean out your fan and make sure you case is getting proper airflow too. A nice couple of sprays of compressed air should do the trick.

Air spray is not recommended, because it often contains moist air and we all know that water and electronics don't mix very well. To remove dust, I use a hairdryer. That way, there's no risk of damaging anything.

Also, if your fan/heatsink is not dusty, it might be the fan that has died. You should also check its connection to the mobo. It might have come loose.

Good luck,
al360ex

^It's called turning off your computer and unplugging it before you do anything. Heck, you could wash it with water, let it dry, plug it back in and turn it on again.

On the other hand, am I the only one who would feel very uncomfortable using a hair dryer to heat up all the components on the motherboard? Especially the ICs that weren't designed with heat in mind?

Even if you turn it off, then unplug it while you spray it, there could still be residual water on the components. Also, he'd have to take off the battery on the motherboard...thus losing all of his bios settings. Also, you never know if some electricity might still be stocked in the capacitors.
As for the hairdryer...pretty much everything on the motherboard is made to resist heating. Also, on recent hairdryers, you often have a function to blow "cool" air, if you want to be extra careful.

I used to work as a SMT machine operator. To take you through the paces of how your board is made in the first place... the blank PCB will run through a machine called a Solder Paste Screener which will apply a little layer of solder paste to all the metal pads. Then the board is sent through a pick and place machine where it does just that... picks and places all the surface mount parts and sticks them to the wet solder paste. Then when the board comes out, we ran it through an oven to cure the solder. After the board has cooled, then it is run through a machine that washes away all the solder flux and residue with ionized WATER.

After that stage the larger parts are added by hand on an assembly line. Then the board will be tested on the assembly like for operational status. If they work then they will once again be sent to the washing machine to remove residue from the hand soldered parts and other foreign contaminants. So even after voltage has been applied to the board, it can still be washed with ionized water.

At home I would not recommend you clean your parts with water from the tap because it is not ionized and will cause corrosion to the electrical contacts. As long as the board is completely dry after being washed with ionized water... you can still use it whether or not voltage was applied before or after (it will simply discharge in the water anyways, not in the parts). The biggest enemy of electronics is static electricity and foreign contamination... not water.

This poster does have a very valid point that there is usually some residue left from the canned compressed air (it's not water), and it is not wise to get the parts wet with an oily residue that may be conductive and cause your computer to short when you re-apply power. I would not recommend a hair dryer, but then again, your board will pass through an oven during it's SMT solder paste curing stage. So the heat will not damage parts or solder joints it if it is not over 3 or 4 minutes. But then again, most hair dryers do not push the air fast enough to actually do anything.

The best way to remove dust from clogged fans or a clogged heatsink is to remove the parts from the computer and clean them gently outside with an old toothbrush. Clean the fan blades and heatsink fins well (no chemicals needed). Also if you need to remove the CPU heatsink, you should use high grade alcohol with a coffee filter or cheesecloth (never use fibrous materials like cotton or tissues) and remove all the thermal paste on the CPU and the heatsink. Never re-mount a CPU will old thermal paste.

After you are done cleaning the fans and heatsink... apply some new thermal paste per package instructions and re-mount the heatsink well, then plug the fan connector back in and boot the computer with the cover off so you can verify the fan is moving correctly.

If your heatsink is mounted properly, the fan is working properly and your CPU temps are not over 50C (best if it is 30-40C) in the BIOS HW monitor... heat is not why it is crashing.

You have a knack for stating the obvious.

Obviously you have to wait a significant amount of time for it to dry. Of course you have to remove the battery.

Also, you never know if some electricity might still be stocked in the capacitors.
I see you don't know how capacitors work, do you? With the exception of those in the power supply, they will all be discharged within 10 seconds without power.

It might be obvious for you, but not for someone new to computers, or who has never done this sort of thing before. Better to be careful and stating something obvious for us, than not saying it and as a result be responsible for him frying his motherboard.

As for my knowledge of capacitors...Did you know that the formula for calculating the capacitance is a logarithmic one ? Which means that voltage "stays" in the capacitor for a very long time, even though it is too small to light an LED on your board, for example.

Also, have you never removed dust from your power supply ? I have. it was full of it. And as you implied yourself, the capacitors inside the PSU are quite bigger, and take a lot longer to discharge. Up to 10 minutes or more, in some cases.

Anyway, as 1965ohio wrote, the best way to clean your PC is to do it piece by piece (with an anti-static wrist band, if possible. If not, trying discharging your body by touching the PSU often). That way, you'll be certain to remove all of the dust.