Good Riddles

Question: A man was found dead in his study. He was slumped over his desk and a gun was in his hand. There was a cassette recorder on his desk. When the police entered the room and pressed the play button on the tape recorder they heard: "I can't go on. I have nothing to live for." Then there was the sound of a gunshot. How did the detective immediately know that the man had been murdered and it wasn't a suicide?

Question: A container that takes no keys,
but a golden delight lies within me.

What am I?

Question: Without fingers, I point,
without arms, I strike,
without feet, I run.

What am I?

Question: Queens can move horizontally, vertically and diagonally any number of spaces as illustrated. One piece 'attacks' another if it moves to the same tile that the other piece is on. How can you arrange eight queens on the board so they cannot attack each other?

Question: I'm in everybody but everybody still wants me.
I won't feed you but I'll feed the tree.

What am I?