Laptop screen is black when the laptop is on.

My laptop is hp dv2000. When I watching a vedio with connecting a charger suddenly screen is blank.But power light is on,caps lock light is blinking,WiFi key light is orange.and charging light is orange when the laptop is off.but when it turned on the the power light is white. I was triad all those steps like hard rest,open ram and clean it .connected with a external monitor.but anything is failed.
After what can I do please help