File this under "duh-uh" .... my laptop only has one USB port. So I've been using an adapter for multi-USB port hub (passive) for wireless mouse, fan, external hard drive fan and 10-key punch. Anyway, sometimes I would loose the wireless mouse, there was twice where I transfer some files to the external drive only to loose these files because the external hard drive disconnect. So I got a powered USB port hub. I don't have that problem anymore. Carry on.