HP Pavilion DV4T-2100 model running windows 7. Today when I turn it on I got black screen and it is not showing anything at all. Everything else is working. I can hear fan noise, LEDs lights are blinking and even I can hear window welcome tone when window starts and also as I know my first screen is password screen when that tone is played I type password and press enter and I can hear sound that is played when user login inside system. Only thing that is missing is display as screen is completely black all time. I have done removing battery and pressing power button for 30-60 seconds many times but no success. The screen is remain black all time. Please tell me what is the problem. Is there any defect with hardware or I have to replace anything.
Edit: When connected to external monitor display is showing up but when display is switched to laptop it does not shows up anything it remains black(not completely black but bright black screen). Is there a fault with laptop screen or wire that connects with screen to other part. What is possible fault if it is working with external monitor.
Edit no. 2: Got it checked from a technician and he told me that it is motherboard fault and it needs to be replaced. Is he right about it? Please share your experience if you have replaced same problem.
Thanks in advance.