I have not used my macbook in a couple days, and it was not like this before. When I open the screen there are blue vertical lines that are flickering on my screen... if i tilt the screen then it goes away but if i tilt it back then they come back... it seems to be only when the screen is either a very light color or white. What is the issue and how do I fix it? It is a 2013 so it is not under applecare.. is there a cheap way to fix it or do i need a whole new computer?? I am not a computer person at all.