White screen after white lines

About a year ago my screen I noticed some horizontal lines appear and then disappear on my screen. After about a month the screen went white and I couldn't do anything, the laptop works fine I plugged it on an external monitor and it was just fine. I did some troubleshooting on the back of the screen and now it's black I tried plugging the video cable I tried disconnecting and connecting the ram it's still doesn't work.