oh, you people, i laughed so hard i almost fell out of the chair.......picture me banging this real little mouse on the desk because it won't work.......then i'm going to take it apart and clean it's ball........oh, no........this is way too funny for an old lady like me.......love, pat p.s. seriously, it is a rollerball one and i'm going to dissect it and we'll just see what transpires.......thank you so much.