And again no. There is no USB to firewire that I've ever found to work. There are folk ready to take your money and then walk away.
As I read the service manual at
Page 38 shows 4 PCI express slots.
Are you saying you already filled all of those?
My new computer (Dell XPS 8300) has no place for my Firewire card from my last PC. What gives ? Is there a way to use USB. My Canon ZR 950 only uses Firewire to transfer video.