From the start. I called Logitech Support today. I told them about my MX Revolution problems, so they told me to send them my used mouse for a new one. They told me an address over the phone, and I was not quite sure if I copied the address right. What I got is this: Logitech Return Center 4149 37th Street Phoenix, Arizona 4(or 8)5040-1842 If there is someone who was in the same situation, please respond.