7'' display flickers and then the device turns off

I got my enhanced Lattepanda about a month ago with a 7'' display and touch panel. when I plug everything and turn on the device, the Lattepanda loading screen shows fine. but when the system is booted the display flickers (between on and black screen), and after a few minutes the device turns off. A friend who visited me told me the display might be faulty because there is a "plus-sign-like shape of white lines" on the screen. Worth mentioning that an HDMI screen works fine.