Answer:
You find me behind the stars; or in a sixth seventh or third. It takes something round a computer and me to make pie. I am bigger than anything you can think of.
A large oasis in the desert. Come with cash and leave with none. What am I?
What is made of wood, but can't be sawed?
Without me everyone would lose their head.
Can not be bought, Can not be sold, Even if it's made of gold. What is it?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.