Hp laptop, very faint screen :(

Basically when i turn my laptop on, you think the screen stays black. But if you tilt it to the right angle you can faintly see whats on the screen. It happened a few weeks ago and i sent it back and hp replaced the screen. Got it back and it worked for 2 uses then did the same thing again. Im starting to think that its not a problem witht the screen and just some crazy power saving settings but I've no idea what. I left it on while i went out and the battery ran out so when i got back to it, it was off and it happened when i turned it back on. So im thinking that the settings kicked in, then it turned off!?!?? But I have no idea and i'd really appreciate some help.