hdmi to hdtv - watching stuff, pic goes green
 

hi guys
i have connected my laptop to my tv via a hdmi cable 1.4 (latest one)
and when im watching something, the screen on my tv goes green and i have refresh the hdmi selection and then the picture quality is fine, but the laptop one is fine all the time.

i have duplicated the screen (laptop to monitor)

is it a problem with the tv? hdmi cable?
have i got to change settings on laptop?

can anyone advise