Hi, I've got a wireless Apple mouse (not mighty mouse) one button with the scroll ball. Its worked fine for about a year. Suddenly the scroll ball only works when I scroll up - no down anymore. And now after a day of that I notice sluggishness of the whole computer when it comes to typing, moving the cursor, highlighting words or phrases, etc. Even the keyboard is responding slower. What's up? Thank you for your (hopefully) suggestions!