How do i stop my laptop fan from going on and on and on ?

My problem is quite simple yet it is driving me nuts !!
Well, me being a fan of n.c.I.s. I have dvds of the first four seasons and while I'm trying to watch that my laptop fan just starts up for a while then stops then starts and stops and starts and...

stops and it oes on like that . Since this is happening when I get to a quiet scene in n.c.I.s. Or a very emotional scene it's ruined because of my stupid fan, then I have to rewind and watch it again which spoils it for me .
I went online to another question and answer site and found someone with a similar problem and someone else answered it saying blow into the compartment where the fan is . The person who asked the question voted that the best answer so I decided to try it myself and to make things worse the fan got louder and even more scratchy which in turn makes me a living nightmare to stay in the same room with .
I'd really appreciate it if someone could help me to try and stop this .
Oh, and one more thing, I don't need anyone to tell me that I was stupid to blow into the fan compartment .

The issue is, if you turned off your laptop fan, you would overheat your laptop in record time. While there are applications that can control and even deactivate your fans, doing this on a laptop would mean that after an episode or two, you would have melted your hardware! Why not just get speakers or headphones?

Hmm, I'm not sure why that is if you take a cleaner and clean the fans, then hopefully your fans on your laptop will be quieter.
Or, get headphones or some speakers. Or another thing you could do, and I did this, get a portable DVD player. I know that they aren't loud as surround sound but they work without interference.
So, I'd either clean the fans, get headphones, or get a DVD player.

I don't know the answer because I have the same problem but mine does it when I'm surfing the Internet. I tried changing the power plan/settings/both but it still does it. I think it has something to do with the computer being idle..dunno. I wish I could help you,maybe someone out there could help us both.