string ringing, buzzing, etc.

[Bec and John]

Hi,

Ever since I bought my piano the G above middle C was mostly 
"untunable" - in that there was a high ringing wave that wouldn't go 
away entirely, but it was tolerable. Actually, many of the notes 
between middle C and the octave above have this sound.

Reading through the list I thought it might have to do with string 
levelling and I noticed the middle string was a bit lower. So I pulled 
it up a bit, really just a bit. Now it's worse :) Not tolerable 
anymore.

I'm desperate for a solution! Any ideas? Thanks.

- John