First, sorry if this is not the right place to post this, but here we go:
I got steam-engined PC (so f**kin' true), and mostly in the summer, there is an awful squeak noise coming from the graphic card or form the hard disk, I don't know for sure. The noise is coming when I'm playing games that need quite a bit of resourses, some various multitasking (MSN, browser, Winamp, Word etc.), today I even heard it when I was watching a HD movie on youtube FFS!! It's happening mostly in the summer because it's hotter, I think.
I KNOW I should upgrade my PC immediately, I'm waiting for my father to come back from his abroad job.
The noise is a squeak, high-pitched and annoying!!!!
Very similar to this. But not that long, it's just a second. But, still, It makes me wanna shoot the dog!!! 
And sorry for the teeeeeeeeeeeeerrible English.