Evo N1015V LCD Screens lights up and then goes black

I need some advice on what to do next.

My Evo n1015V LCD screen light up normally when I put mynotebook on. then after a minute or so the screen goes dark.

I have already taken it to Compaq and had the inverter changed twice but the problem is still persisting. They said that I need to change the screen.

Can you help me out on this on what could be the cause of this problem and any advice what to do would be more than gratefull