thanks, I just got a new mouse, both logitech, but the new one is a wireless one w/ a keyboard, and the reciever has a cable for keyboard and mouse, and the one for the mouse is USB, which I can change to PS2. But between the two mouses ive had, there is a HUGE noticable performance decrease in the speed and smoothness of the mouse, not only in feel but visually. My old mouse looked smooth and crisp as you moved it around the screen. My new one is a fluttery and skippy. Not slow, but not nearly as crisp or responsive... possibly since its wireless?