Strange sounds coming from computer?

>I'm having trouble with my new computer. every so-often i'll hear a chirp. like once every day or so. a chirp coming from inside my tower. it sounds like the high pitched beep that the motherboard speaker makes when loading for the first time
>also, this electrical buzzing sound that sometimes comes from the tower
>and when i plug headphones or speakers into the front I/O port, they have this weird buzzing sound. but when i plug them into the back i/o port, they work flawlessly.