I would open the back cover with a flat metal opening tool like this: http://www.ebay.com/itm/Tech-Metal-Spudger-Opening-Tool-for-ASUS-Nexus-7-1st-2nd-Gen-ME370T-ME571K-NEW-/161561753109?ssPageName=STRK:MESE:IT then disconnect the battery 1st before anything. Check the LCD cable which is silver and runs from the MB to the LCD top to bottom over the battery. It looks kind of like a stick of gum. They often become loose and just need to be reconnected and secured better with some electrical tape. Be careful with the clips. I'm almost certain that is where your problem is and you should be able to fix it without much trouble. Good luck
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I would open the back cover with a flat metal opening tool like this: http://www.ebay.com/itm/Tech-Metal-Spudger-Opening-Tool-for-ASUS-Nexus-7-1st-2nd-Gen-ME370T-ME571K-NEW-/161561753109?ssPageName=STRK:MESE:IT
then disconnect the battery 1st before anything. Check the LCD cable which is silver and runs from the MB to the LCD top to bottom over the battery. It looks kind of like a stick of gum. They often become loose and just need to be reconnected and secured better with some electrical tape. Be careful with the clips. I'm almost certain that is where your problem is and you should be able to fix it without much trouble.
Good luck