recent apps and back button not working

[AC Question]

The screen on my tablet started flashing and then had a black screen. I charged it overnight and the screen was fine. N I w, the recent apps and back buttons are not working. I reset to factory settings and nothing. Please help....

 

[Rukbat]

If they're hardware buttons, something physical went and has to be replaced. Otherwise back everything up (see Backing up an Android Device) and reflash the stock ROM.