Ground yourself before you plug it in.
This is the most common 'cause of damage to the motherboard throught he front port panel. Often the usb and firewire ports are exposed metal-socket ports. If you've got a good amount of static electricity in ya (especially during these winter months when the air is dry and carpets are excitable) and you touch the ports (or the internal sockets) while the machine is on, you can fry that puppy easily.
I can, at will, make just about any machine reboot during the work day just by reaching over and touching my index finger to the front firewire socket. Zot, POST.