I woke up to my laptop fan screaming in my face and out of shock I switched it off but the sound was so alarming, I was so confused. This morning I switched it on and it did the same thing then I took it to my brother to look at and he got tired of the loud noise the fan was making so he hit the table under the laptop and the noise instantly left. Once in a while, it does that again and I hit the table under it and immediately the sound disappears...please what exactly is happening with it?