Creepy sound when Idle

so, im having trouble with my router, all of a sudden it stops sending IP information so i have to reset it, but thats not the point.

The thing is, recently, i decided to sit in front of my computer and wait for the net to go down again, just staring at the desktop, when i heard a creepy "whoosh" sound, the kind of sound that comes out in those scary movies when the guy looks into an empty room. It didnt sound like a system sound but it definitely came from my speakers.
I wasnt running any programs, and im the only user of the computer so there wouldnt be any extra junk im unaware of. Immediately after the sound i checked the processes, but i found nothing out of the ordinary.
Is there any explanation to this noise? It comes out randomly from time to time, but i always dissmissed it as a system sound. Its starting to worry me now because it came out while the computer was completely idle.

!!!!!!!!!!!!!!11

I was not the only one! Randomly I hear some weird sound from my speakers not very often. But it does happen, and I was also wondering what it was. The computer is completely at idle state, and it is a bit creepy when it happens. Can anyone explain this phenomenon?

mine does that too......................it did it even after i completely wiped my HD and reinstalled windows too........

>>1-3

It's obviously a ghost!

Wait a second... You guys don't have NetStumbler installed, do you?

My laptop did that once. Turns out what had happened was I was working in an office which had a printer with an infra-red transceiver on the front. My laptop had picked up the infra-red from the printer, recognised the device, made a "zong" noise, and automatically installed the printer! It took me a few seconds to work out what had happened. Windows will pick up any IRDA device in range of the sensor (printer, another computer, mobile phone, etc), and make that "zong" noise. Then when the device goes out of range, it makes a "whoosh" noise. Even people moving around the room can deflect the infra-red beams enough to make devices appear to randomly connect and disconnect.

You should take an audition to be the next Ghost Whisperer..