Windows failed to start. A recent hardware or software change might be the cause..

hello

i tried to install windows on my mac via bootcamp, first i started with bootcamp assitant and it worked with external superdrive and usb which has been downloaded bootcamp drivers on it, but suddenly it stoped working and picture below appears, then i found out that i would have installed new bootcamp manually , so now i have downloaded it and replace with older ones, but still does not work and still same error, what should i do?please help me,