Go to Start, Control Panel, Hardward and Sound, then Mouse. Your mouse and touchpad software should open where you can do this.
Touchpad, an input device commonly used in laptop computers
Do you mean iPad? If not I don't know
well for the wii you shake the remote, but for the PS3 you have to press LT RT a couple of times. Hope that helps you. Edit...
You either keep battleing in your ladder, or you could try doing A or S ranked missions, I'm pretty sure it's one of those missions. It might tell you who you could unlock.