My tablet set to 1970/01/01

[AC Question]

Yesterday i downloaded at my lenovo tablet kingroot and after some minutes i unistalled it. after some hours i decided to turn off my tablet. when i turned it on the logotype of the company was loading for about 4 hours until it turned off because of low battery. when i charged it i saw that its chronology was set to 1970/01/01. i had downloaded kingroot and then unistalled it so many times but this never happened before. actually sometimes it was taking it about 30 minutes to turn on. But now it will never open. i am not planning to visit any expert because my parents will get mad. Please help me and sorry for bad english