My PC is experiencing some very strange power issues. For one, when the computer is running, if anything is plugged into the backplane (USB 1.0/2.0, IEEE 1394) it immediately shuts off. Following this, I have to give the machine at least 10 minutes to dissipate charge before it will start up again. I've already tried switching outlets and power cables. The only things I have plugged in the backplane are an old serial mouse, a PS2 keyboard, 1 Firewire device, and a standard VGA monitor. Any ideas what is causing this / how to fix it?