lots of white squares on start up - Inspiron 15R 5520 - i need to change the angle of the screen 5 to 10 times to get it to start up ?help please!!

Inspiron 15R 5520, Hi i know I need a new battery, but on the mains start up sometimes its fine, other times i need to change the angle of the screen 5 to 10 times to get it to start up, otherwise I get half the screen filled with white squares and beeping. I have to keep closing and re opening the lid until it starts up on a normal screen. Once started and open i can move the angle of the screen many times without issue?  many thanks for any advice guys