Dan-
Peter has some good suggestions. If you still can't find the noise suggest 
you-
1. Get a piece of rubber or plastic tubing approx 18" long, 1/4 or 3/8's dia 
and put one end in your ear and search around the board for the noise. A 
small plastic funnel inserted in the end of the tubing will help get you to 
the general area, then remove the funnel and search individual components. 
OR-
2. If you have and can borrow an older type of stethoscope, the type that 
have a lever at the end so you can change it to open air or closed cell. 
Search around the board with it.
Hopefully this will find the source of the noise.
You will probably find it coming from the fan on the video card. They are 
small and many turn at a rather high speed.
HTH
John Dinges 

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