The board has onboard firewire and I have also a firewire card (PCI) installed. Both ports work when the PC boots up for the first time. When the PC goes to sleep mode and wakes up BOTH ports are gone in Device Manager! A reset doesn't solve the problem. I have to shut down the PC, unplug the power cable and power it on again. Then everything works again...until the next sleep mode.
Try to install the An IEEE 1394 isochronous device does not function in Windows 7 SP1 or in Windows Server 2008 R2 SP1 hotfix, it includes latest version of OS IEE1394 system driver. The number of IEEE1394-related hotfixes for Windows 7 is just...terrific. Consider a try of Unibrain replacement drivers - Unibrain Software Download Section , at least they make basic work stable.