Extremely high pitched noise just came and went from my PC in the space of about 2-3 minutes In that case things are starting to make sense - for a few months I've had an annoying 'rickety' sound coming from a similar area in my machine when I start to do intensive tasks on the desktop. This rickety sound (like a fan hitting something on each rotation) was present prior to the high pitched noise described above but hasn't appeared in the few hours since even though I've been working with the same apps on desktop. Related?