Computer is framed, software is all configured, but one annoyance remains: a 13.5khz whine that I have isolated to the CFL backlight driver (I thought). I need to quiet that down or it'll drive me mad!

I tried foam insulation around the frame - didn't do enough. I super glued a bar of aluminum to the high voltage transformer - no change. I covered the entire driver board in putty... minor improvement? I tried grounding the board to the chassis, no change. After all this it appeared the sound might also be occurring on the motherboard itself.. at this point I've a bit deflated and moving on to other projects for the time being. Open to suggestions!