Its easy to pin these down. Go to settings system/hardware and right click and select properties for the device that has a question mark on it.
Write down the two value given under details for the VEN and DEV parts of the string found there.
Go to www.pcidatabase.com and enter these values in and it weill instantly show you excatly what this device is. Then go to the m,anufacturer site and download the driver you need.
Simple really ?