High pitch noise from computer under any kind of load

Hi people,
My computer has been doing this for as long as I can remember but it's driving me crazy! Under any kind of load; opening a folder, opening a website, pressing enter, anything that puts the processor under a small amount of load I guess, produces a high pitch sqeek which is really, really annoying. I'm not sure what would be causing it, hard drive? CPU? Heat sink? I tried kicking the computer a few times which usually fixes any funny sounds that come from them in my experience but this one just keeps on sqeeking! Any ideas on what might be the cause? I don't mind opening her up and having a poke about, I just haven't had the time for a systematic check of all the components; I have a thesis to write.
Cheers

 

Its a bit common actualy, its normaly a sign of an overworked PSU. Mobos can do it too. My infinity does it from time to time... Its the "chokes" that "sing" a dab of hot glue normaly fixes it right up ...

 

Thanks, I would have never thought of that!
I'll try the glue.
Cheers
A;ex

 

Yea just enough glue to keep the coil from moving loose on the "core"... if that dosent fix it, its prolly the chokes in your PSU. In that case id get a new one as singing chokes in a PSU is a bad sign...