I had it custom built and when I got it back I needed to open the back to fit in something (under the guidance of the Tech Support). Anyway, I've just opened it up again and there are three fans.
One for the hard disc, one in the motherboard (CPU?) and one in general. All are working, all is cool, but the sound appears to be coming from the motherboard area.
As said, this is the worst time of year for it to happen and if I have to be without it over Christmas it's going to be pretty miserable around my household
