is there a way to change the speed of my fan?
Here is a quick guide on controlling Fan Speed:
That was exactly what I was going to post. The fastest wins, I guess.
Do you think it works? Is that when doing many things the laptop heats up and although it is very hot the fan does not turn on
It should work just fine.
Why does this happen?
You have neglected to tell us what brand of computer, you are trying to change your fans by via software.
I have an MSI computer, and there is no software on MSI, that will allow me to change fan speed, due to the hardware encoding method they used. The only way I can change fan speed on my computer, is in the BIOS.
Lets just hope you don't have an MSI computer lol.