I don't know what is the exact issues or what help is asked in this thread.
For 7900 Series, AMD introduced ZeroCore Power to put the cards to sleep to save power consumption.
You will see the second and third card dissapear/downclock when they are in ZeroCore State.
To see all the cards in action you must run applications that support crossfire in Full Screen Mode. You can easily monitor this with the second monitor.
Is this your problem?
Or you are having BSODs overclocking with third party applications? Or you have conflicting softwares in your system? If so, do a fresh Windows install and start fresh. This is not neccessary if we know how you configured your OS.