hi i was watching a video and suddenly my laptops screen displayed some error i took the battery out but now when i am applying the battery my laptop is getting on but the screen is black but all the indicators on keyboard are on what to do now please reply asap my laptop is HP pavillion dv6

Hi there.
HP Pavillion DV6 are REALLy well known for doing this. there is a big law suit against HP about the design flaw. the heat-sinc isn't sufficient for the CPU and GpU, and the GpU (graphics card) dies.

you can hope that's not the case with you, but then again, it happens so very often on this model...

(I can't hyperlink that properly, you need the "(computer)" in the link to get to the right place)

Overheating issue
Many notebook owners experience hardware failure in various Pavilion models due to overheating. The first symptom is usually a disappearing Wifi. Later failure of the graphics system and booting problems. HP does acknowledge this as a "hardware issue with certain HP Pavilion dv2000/dv6000/dv9000" notebooks, which is eligible for free repair.[7] Other users recommend a "resoldering" of the nVidia GPU on the motherboard.