Ecartes argument on the existence of God

Write an essay which evaluates the argument that Descartes uses to prove the existence of God. To evaluate the argument, you must (a)present it clearly for the reader, (b) take a clear position on wheather the argument is valid or invalid, sound or unsound and (c) support, explain and defend your position. To do (c) you must show awareness of what it means to say that an argument is valid or invalid and sound or unsound, and oyu must seek to convince the reader that your view of the argument is correct. Why do you say that the argumnet is valid or invalid, sound or unsound, and why should the reader agree with you? Support and defend your position on the argument as best you can.