OT: High pitch buzz when recording

[Andrew Robinson]

I am trying to record on my Fedora 9 box with audacity. When I do, the 
recording includes a high pitched buzz on the right track. I have 
unplugged everything from the sound ports, and still get the buzz. I can 
  see the right channel has a higher level on the input meter when 
recording. This is an six channel on-board nVidia audio on an ASUS 
motherboard. Anyone have any idea what causes it? Am I likely to be able 
to fix it?

Thanks!

Andrew Robinson