Hp envy black screen during boot

Hi,
I have an hp envy 15 laptop. I had it on dual boot with windows 8.1 and ubuntu 14.04. The problem started with random black screens while waking up from sleep on both Os. Now I can barely boot properly. I had to boot 14-15 times to be able to get something on screen. And the laptop works perfectly once the screen shows up. I have also tried a full factory reset in hopes it would fix the problem, so currently I have windows 8.1 only. Most times although the screen stays total black , it seems everything is working on background. Pressing f10 repeatedly does make beep noises, indicating it is in bios.

Things I have tried:-
Power drain
F2 dignostics
Full factory reset and reformatting everything
Bios updates
Driver updates
Disabling graphics cards from windows (tried both intel and dedicated nvidia - there is no option to do this in bios)
Tried taking this to HP service center and they have no clue about the problem

Ps:- Hp is refusing to fix the issue on grounds that laptop was bought on a different country even though the laptop is sold and supported here. Please also let me know if any of you are aware of any solution to this situation.

 

When the Envy line first came out (when try were considered a premium device) the first year of warranty was international with the 2nd year of warranty only being active in the place of origin. I doubt it is the same now.

Could it be that the inverter has gotten loose?

If you close and open your laptop a lot maybe you will notice that it suddenly turns black because the cable might not be fitted properly. Best thing I can think off considering the screen is black during boot.