How do I check if my laptop fan working properly?

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http://askubuntu.com – I have an old Dell studio 1558 laptop (2 years) with Ubuntu 12.04. Its always make some noise, some time the fan make a terrible noise - and I must quickly shutdown it by press the power button 5 seconds. When the terrible noise the laptop take really long to shutdown with the normal way (or event terminal with shutdown -h now). I just install new Windows 8 for testing, with Windows 8 there is no noise with the fan. But I can make sure because I just use Windows for a few minute. So is there any way (some command or program) that I can check if my fan is working properly? Does the fan ne (HowTos)