Do you keep the vents clear? If you use your laptop on a cushion on your lap, for example, it will overheat.
Buy a tin of compressed air and use it to blow in to the vents and over the keyboard.
If you are running a lot of demanding processes at the same time your processor will struggle and overheat - have a look at the task manager and see what is going on when it makes that noise.
Don't be frightened of opening up your laptop - there are plenty of videos on YouTube to give you step by step instructions for your make and model. If you can expose the fan and blast it with air it will improve things enormously - you will also be able to see that it is still working properly.