Why is the screen black and white with a buzzing sound?

My GameCube has worked for a long time until my twin brothers moved out, so it didn't get played for a little while. I remember we got a new TV a while ago and I remember playing Starfox Assault and Legend of Zelda Twilight Princess on it just fine. I picked up the controller again lately and started playing, but the graphics are kind of messed up and the nostalgic music is replaced by a really annoying buzzing sound. The TV is 4 years old, I tried different games and they are all black and white, I MAY be missing a cable, but as of maybe last week, it stopped working on the TV at all. The gamecube will have lights on and the fan will turn on, the disc will spin, whatever, it just displays "No signal" on the TV screen.

I'm also just wondering, what cables do I need to play the gamecube properly? Hopefully besides the very expensive original AV cable.