I got a new computer HP 760n, with an optical, corded mouse. The first thing I did was go to eBay, search out "cordless mouse", and within an hour, bought the "Microsoft Intellimouse", cordless version. I love it, it fits my hand, and has no ball to get dirty. I added a Logitec cordless to my old computer, & would not go back to a corded model at all. I have too much clutter on my desk as it is, and the original mouse cord was always dragging or caught up under stuff.