My tv makes a whistling sound when connected to PC?

Does it whistle because it doesn't know the words? Just having fun with ya. The noise might be caused by electrical interference between the TV and computer. Have you tried repositioning the computer - putting it one side of the TV, and then the other side? Have you tried a shielded HDMI cable? If you're comfortable around high voltages, try wrapping a wire around the HDMI cable, and then grounding it - computer chis, or the "ground" in the AC outlet.