HP Compaq 6710b and TV

Hi,
I have a laptop that I use to watch movies on my TV.
By cons, when I close the lid, the screen goes black on TV.
So I can choose if I want the image on both screens or just the TV.
But if i can not close the screen, it's not convenient …
Anyone have a solution?
My PC is an HP Compaq 6710b.
Thank you.
