my android tablet keeps rebooting itself when i power it down and it will not let me download things from the store i mean it will let me click on install and everthing but it will not download it nomater what.also if i stay on google to long on it it will freeze inwhich i have to power it down wich makes it reboot itself.also if i try to reboot myself then it will give me a robot with an open chest and red traingle in it.