Hi, what makes the phone not to display is because the flex of the phone is BAD and damaged.
The flex of the phone is located inside the phone, it controls the functions of the screen an also the keypads of the phone.
The flex is a thread like object that is located inside the phone. To see the flex, you will need to disassemble the phone to get to the flex of the phone.
After replacing the phone flex, your done.
Also it might be the screen of the phone. But in other to know if it's the screen, you will need to test a new flex.
You can get a replacement flex from any of the phone repair stores around you.
You can see how the flex looks like below
Hope it helps.
Thanks for using fixya...