Help me diagnose this sound

As the title says. The first sound is a fan (no idea why but can assume both sounds are related) but the 2nd is just strange... 

This sound has started happening and my computer has started turning off. 4 times in total over the last week or so. It'l then boot up fine with no error messages or anything, as if it never happened.


Thoughts?

http://www.youtube.com/watch?v=p3ChRG0UsjY&feature=youtu.be

I have no idea what that sound was. Kind of seems like it could be an optical drive sound, mechanical hard drive, or some other part that moves. 

Beyond that I think your PC might be turning into a T.A.R.D.I.S.

Sorry I can't help. If you could say exactly when in the video the sound starts or get a better audio recording maybe that would help narrow it down.

There are 2 noises, 1 after the other.


The first is a fan reving up and the second is the same but lower pitched and longer. Much more mechanical sounding too...

 

EDIT: Just had a look and I think its my GPU HD6790.
The first fan noise is.

[img]http://i3.photobucket.com/albums/y92/Terratora/Capture_zps227d4f62.jpg[/img]

Found an HD6950 which I will pick up tomorrow. We will see if it is that then!

 

To be continued...

UPDATE: Fixed!

New card is in and working perfectly. The old HD6790's fan is so stiff that it wont even spin freely. Will give it a clean out and sell it on, I expect.