I just purchased a 2.8 Ghz 24" iMac, plugged in my firewire drives and firewire no longer works. I have a 20" 2.0 core duo, upgraded to leopard, and now firewire does not work, to make matters worse I believe my MacBook has a dead firewire, what do all this have in common? Leopard I have different brand drives and also a firewire DV camara, none work