Is it possible to use a game controller as a mouse?

Why cant i use my mouse on my xbox360?

• ok so simple question, but i believe the answer is much more complicated. The xbox is a powerful computer that can run advanced games. I want to buy portal 2 for it but i played portal 1 on the pc, and think it would be really limiting to use a controller. the problem is that my current pc can barely run the first game and i want to play it with a good frame rate and high quality graphics. why cant you use a mouse and keyboard to play games? is it because consumers would switch wholey to using the pc as a gaming system when they learnt to use the mouse? or would it discourage gamers who cant play fps using a mouse and keyboard from playing? the mouse to me, is freedom in every way, and it irritates me that i cant use it for gaming on my xbox. what do you think?

• Answer:

  no mouse because there is the analog sticks also a keyboard does work but not in games. They do this so people have to spend 50$ on xbox controllers