MacBook Air With Nothing Visible On Screen Except Lines
This MacBook Air has a common issue that I see a lot on this model. There is a hairline crack on the left side of the display right where the horizontal lines start. Because the data is not able to travel up the screen properly, the display only shows what is visible in the picture when it is powered on. This means the computer is not usable unless it is connected to an external display.
I replaced the cracked LCD panel and now the computer is fully functional again.