Hey there.
Long story short.
1 long 2 shorts vídeo card problems could not initialize
1 long 3 shorts vídeo card not detected or damaged
And Last but not the least
550watts for 6700XT is not enough let alone if its an AIB.
Power off the system, take out the power cord, remove the card and let it be for a while. Clearing CMOS could also be a good ideia.
Good luck
The Englishman