You've given yourself a nice upgrade. And I think you're on the right track for the fireware card. It's either the card, or the card drivers were corrupted. If it's the card drivers, UNINSTALL/REMOVE the device from the device manager, and then reboot and let the system auto-find the hardware again.
I lose hardware like that from time to time, this is always the fix. Not long ago, Apple
iTunes 6 made my DVD burner disappear. I had to uninstall
iTunes, and then delete the DVD burner from my device manager, and then reboot. It was detected, and all was well again.