I see nothing but a Green Screen after recording videos with my security cameras

hi all,
i just bought a new Provision Camera card,
installed it on my pc and connected to it 4 cameras ,
now i see the 4 cameras on my pc and everything wroks fine .

the problem is that i see full Green screen when i playback the recorded video file .
its the same with all 4 cameras ,

anyidea what could be wrong ?
thanks

You just might not have enough power in your computer to record the 4 videos at once. I would see what is recorded with only one camera. If that works try 2 and so on.