Uninstalled, removed crossfire cable, re-installed crimson, replaced crossfire cable. All fine now. Ho hum, I suspect the cable wasn't reseated properly from the first time around.
I've not been able to install catalyst drivers for some time with the crossfire cable in place. I can't have replaced it properly this time; hence the crashes.
Nice, glad to hear you got your setup working properly, was gonna offer some advice but it is not needed. Game on!