For some reason, the on-the-fly sensitivity adjustment doesn't work. I have it set to on and to "show on-screen", but it never changes when I push the button I have it set to. I've reformatted windows for various reasons 3 times since I've had the mouse, and each time I installed the driver/program it didn't work. I've tried both the drivers that came with it and more recent ones from the razer website. Anyone have any ideas?