My hp pavilion shows default screen

drop the battery yet, disconnect it.
the service manual shows how.
see that yet?
screen 100% black all time even with ESC key pressed, power on>
if totally dead and power pack reads 19vdc then
remove the battery.
no full service tag shown so no exact answers possible.
lots of x360 made , many.
if this scares you doing repairs get it fixed in a shop, like 99% do.

can you hear the system working or see the hard drive light blinking ?

Sounds like you need a screen replacement. The bulb that provides the backlight to the screen is going / gone bad.

It is probably just a stuck pixel. As long as the stripes are white it can probably be fixed easily. Read the article below and see if it resolves your problem
http://www.wikihow.com/Fix-a-Stuck-Pixel-on-an-LCD-Monitor

Hi there
i read your report. OK go to your power options and turn off your hibernate and restart your computer.allot of times after you have reformatted your hard driver. the hibernation doesn't work correctly. Try this tip and let me know how it goes. Thank you for writing to fix ya.

Best Regards Richard

If you have already hooked up an external monitor absolutely its the ribbon cable connecting the LCD to Laptop If its less then a year old get the warranty for replacement

No it suggests you have a bad screen and it needs replaced

try enabling PCI option in the bios...
and also update your graphics card drivers for nvidia.com

If you find the same white line in the BIOS screen, we can confirm that it is the problem with the LCD Screen of the notebook.

To enter in to the notebook BIOS uility, start it and keep on tap F10

video driver maby what about redoing windows formatt it all