Hello,
believe in the possibility, which was also cited by card manufacturer's technical support (COMTAC), some incompatibility system after an upgrade from Windows 7 through Windows Update that happens automatically. I did not make radical changes, only update after formatting. I tested the firewire on the other PC with Windows XP before and after the formatting and it worked.
Before formatting I had updated the BIOS.
Talking with several technical informatics and most of them believed to be a problem in the slot. There would be fixed?
SDS
Anselmo