I had this problem with one of my Antec cases during winter months but not in the summer. I concluded it was probably due to static electricity discharging through the USB port and confusing the motherboard.
Try grounding yourself to your computer case (touch any exposed metal on the case) before plugging in the cable.
Another workaround is to buy a powered USB hub, plug that into your computer, and then plug anything you will be disconnecting regularly into the hub. Powered hubs are grounded and will shunt static charges to ground before they can reach your computer.