* Try re-seating the card in the PCI slot.
* Refresh PRAM. Refreshing the system's parameter RAM is sometimes necessary, particularly when installing or removing PCI cards. This is done by holding down "Command-Option-P-R" while restarting the system. Hold keys down until the system chimes three times. Let go of keys and allow to boot up. PRAM is used to store some control panel settings, so these may need to be reset.
* On occasion, the firmware of the card can become corrupted. Run the Express PCI updater to re-flash the adapter firmware.
* Conflicts with other PCI cards. While there are currently no known outstanding uncorrectable conflicts, temporarily removing a PCI card or swapping PCI slots may resolve a slot conflict.