Fan Attached to heat sink in laptop not always spinning?

My laptop seemed to be overheating and shutting down an awful lot so I thought it may be down to dust building up inside the machine. I took the laptop apart and there wasn't that much, which I thought was strange. I put the laptop back together and turned it on, and after not very long it overheated and shut down again. This time when it shut down I looked at the fan that is attached to the heat sink inside the laptop and noticed it wasn't spinning. I remembered connecting it to the main board but thought it mustn't have connected properly so went in and reconnected it.

When i powered the laptop on again I checked to see if it was spinning or not, and when it turned on it span then stopped spinning. Is this always supposed to spin or will it turn itself of from time to time.

(for the record as I have been typing this it has started spinning).

BomberAF said:

My laptop seemed to be overheating and shutting down an awful lot so I thought it may be down to dust building up inside the machine. I took the laptop apart and there wasn't that much, which I thought was strange. I put the laptop back together and turned it on, and after not very long it overheated and shut down again. This time when it shut down I looked at the fan that is attached to the heat sink inside the laptop and noticed it wasn't spinning. I remembered connecting it to the main board but thought it mustn't have connected properly so went in and reconnected it.

When i powered the laptop on again I checked to see if it was spinning or not, and when it turned on it span then stopped spinning. Is this always supposed to spin or will it turn itself of from time to time.

(for the record as I have been typing this it has started spinning).

I ran a search on "Do Laptop Fans run all the time?" in Bing (MSN search engine)...came up with a few articles:

Does the fan on your laptop run all the time or on and off? - Yahoo! Answers

How to Set a Laptop Fan to Run All the Time | eHow

Apparently, they don't run the same way the fan on a tower does. It depends on the internal temperatures of the case...the second link I found gives ways to make the fan run more frequently. (But be warned, this will make the laptop noisier).

Other than looking in BIOS options as Robert said above, another way to get the fan to kick in more often would be to go in the advanced power options of your current power plan.

Write "power options" in the Start search box, then select "change plan settings" of the power plan you are using at the moment, then select "change advanced power settings", then in "processor Power Management" select "system colling policy" and set it as "Active".

Active cooling means that power is used to cool down the device (usually by using a fan), passive cooling is waiting the devices dissipates heat without using power (without using fans), although usually the fans kick in if the heat rises above a certain level.

Of course this works only for the power plan you changed the setting in. So if you use both "balanced" and "power saving", you need to to this twice, once for "balanced" and once for "power saving" power plan.