Question Laptop won't start, black screen no bios access

[Skyrimpro12]

I have tried hard resetting the computer, i have tried connecting external display and still nothing. It powers up and the fans run. The lights come on, though the keyboard backlights turn off soon after. I went as far as taking it apart and checking the hardware for any damage and haven't found anything (hard to search when you don't exactly know what you're looking for). I have run bare-bones just motherboard with ac power connected to external display (with/without OS hard drive attached). I tried contacting Asus about it but they just told me to send it in, even though it's out of warranty, which i declined. I was wondering what i should check and what problems usually cause this behavior. Sorry for the long explanation and lack of info, it's my sister's laptop and she doesn't know much about what went wrong or the like.

OS: Win 10
Laptop: Asus ROG G74SX

Sidenote: Any more info i can provide just let me know. As i don't know what the problem is, i don't quite know what all info is needed/necessary to help troubleshoot. Again, i apologize and thank you again.

 

[ahmeddy]

check this link : https://www.ifixit.com/Answers/View...ot+boot+-+black+screen,+no+bios-uefi,+nothing
your problem is maybe a hardware failure.