Odd situation that I have come across. One of my clients has a western digitial 500gb external usb hard drive. It has it's own power supply and was working fine for what I was told. Anyway, once it is plugged in all of the usb drives on the PC die. The usb mouse, laptop cooler, and usb speakers lose connection. After a quick reboot they all start working again. Now I know that when this happens its usually lack of power supply or a bad usb port. But any of them that I try it has the same effect. Also, it happens on my laptop as well when I tried to test it. Now before I tell them to consider it a loss and buy another external. Anyone with ideas?