I have a rca 52 inch TV that is one year old, and when you turn it on, it makes a very high pitch sound that stays on even when you mute the TV. Eventually after a few minutes it goes away, but it does it every time you turn it on. Any idea's of problem?

RCA's are notorius for this. The power supply is going bad. It will only get worse until you can get it fixed.

I hope you bought the extended warranty.