How can i tell if the fan on my vaio CS31S isnt working properly? It seems to speed up and down and the laptop shuts down? Is it te fan or could there be another reason for this shutdown? :-)

Apparently seems like your laptop is facing heating problem & its because your cooling system including fan inst working properly. You need to check if your fan is running at adequate speed and also there aren't any dust particles stuck in head sink on either side of your laptop. All you need to do is just to use an air blower and clean the fins of your heat sinks to make the air flow properly. Good Luck

It is probably shutting down to prevent thermal damage dut to overheating. Check that the fan is working. Even if it is, if the vents are clogged with dust the machine will not be able to cool properly. The only real remedy is to open the case, clean all the vents and fan, remove the heatsink, clean off old thermal paste and apply new paste before replacing the heatsink and putting back together.

Here is your cpu fan
http://www.ebay.com.au/itm/Sony-VAIO-VGN-CS31Z-Q-VGN-CS31S-V-VGN-CS31S-W-CPU-FAN-/250858713966?pt=Computing_ComputerComponents_Fans_Heatsinks_SR&hash=item3a6858336e

And here is your dissassembly instructions
http://home.comcast.net/~nw_systems/VgnC.pdf

Your pc CPU FAN is not working, you need open it and clean fan,, and under fan, on CPU there is termo cream, don't frgot about it, you need clean it and put new termocream. it is nessasary for cool CPU, that Cpu can not be warm.

This could be a sign that your laptop is overheating. If you touch the laptop while it is running & you find it too hot, make sure that the fan is running properly & that the air ways are not blocked.
You can blow compressed air into the cooling vents of the fan. If you notice clouds of dust coming out, then it might be a good idea to disassemble the laptop, clean the fan & air ways, & reassemble it back. If the fan has failed & is no longer running, it might need to be replaced.

If none of this solves the problem, or is not the case, then you might have a bad motherboard.

This could be a sign that your laptop is overheating. If you touch the laptop while it is running & you find it too hot, make sure that the fan is running properly & that the air ways are not blocked.
You can blow compressed air into the cooling vents of the fan. If you notice clouds of dust coming out, then it might be a good idea to disassemble the laptop, clean the fan & air ways, & reassemble it back. If the fan has failed & is no longer running, it might need to be replaced.

If none of this solves the problem, or is not the case, then you might have a bad motherboard.

kevin,
Is this the pink sony vaio? Looks familiar . . .
The problem with this model of sony vaio is the fan that's why it keeps on shutting down after a few minutes. If you notice there is no activity on the internal fan. The internal fan and heat sink is on the same module.I have already replaced the fan on one of this models and its now working just fine.
just look for a spare fan on ebay . . .
hope this helps . . .

Hi,

Are you having any problems with the laptop overheating or shutting down unexpectedly?

Generally the fan should only run as much as it needs to in order to maintain an optimal temperature. the fan will be turning off as the laptop will be cool enough. if however, the laptop is very hot to touch you may have a faulty sensor telling the fan the laptop is cool when it isnt. this generally leads to the laptop crashing or shutting down though if thats not happening i recommend contacting HP for guidance.

it is most lekely functioning properly if you arent having any other adverse effects

Thanks

there is virus in bios or fan is not working properly.

Try having your battery tested. There may be not enough power to run everything on your comp.
Anotherthing to consider, if your CPU fan isnt working the bios wont start the O.S. as the CPU will overheat and shut down automatically. Good Luck