Laptop making strange crackling sound when idle

[HMS-ratters]

As the title states, my laptop (HP pavilion ak 001 I believe) makes this quite audiable crackling/clicking sound, it only ever seems to stop when I/O is used to change things on the screen, so things like gaming and scrolling web pages yet the noise returns when watching videos. I have tried disabling the mechanical drive to no avail and I'm stumped.

And suggestions as to the cause and possible fixes would be greatly appreciated

 

[jossrik]

The only thing I can think of that makes noise in there would be the fan/fans, replacing thems might be the fix. If something in there is wonky it might not make noise when it's cranking over, but slow it's probably off center somewhere.