One day I was smelling a weird sent of burnt coming from my comp.
I thought that it was benigm, but it became more noticeable.
Suddenly, some fire came out of the fan. While panicking, I directly poweroff the machine.
It was simply due to the fan accumulating too much dust.
I blew all the dust, and from this day on my laptop is cooler and works better...
moral: always blow in the fan to remove dust at least once a week.