Power down before connecting Firewire devices
 

The manual for my Canopus ADVC-100 video converter advises that the device shouldn't be connected to a computer's Firewire port unless both it and the computer are powered down first.

Also, my understanding is that 4-pin Firewire connections do not deliver power. But not all 6-pin Firewire ports on PCs supply power... even though that is the purpose of the 6-pin connection versus the 4-pin.

Just my two cents.