No image, horizontal and vertical lines

I'm having problems with the display screen on my Compaq Presario CQ62, Windows7 laptop. Problem started about a year ago when the laptop started "freezing" up occasionally. I had to power off, restart, and it would start up with no problems. Next problem was "flickering" screen with horizontal lines.I had to slowly move the screen back and forth until I found the right angle and it would work fine, no lines, perfect picture. Eventually adjusting the angle didn't work. The only thing I could get was a blue screen with lines. I hooked up a external monitor and was able to run programs, Facebook, e-mail, ect. using my laptop keyboard but the laptop screen was still blue. I replaced the display video cable but that obviously wasn't the problem cause screen is still the same! Anybody know what I should check next??? I still get audio on the laptop everything works fine (but slow)except the screen! I've tried holding the power button after pulling battery and power cord. I've tried with just the battery, just power cord, and both but it runs the same. One weird thing is the laptop screen changes colors, lines, brightness, ect at start up or when I open/close tabs but no image. The lines are both horizontal and vertical and the screen is mostly white, light blue. The lines are always different colors.