For now, call Lenovo and ask for fix, repair, etc. There are many causes such as malware out there so there's that. I'm finding I'm factory reseting a lot of Android tablets.
why does my Lenovo Tablet turn itself on. I turn it off completely, but several times now, it comes back on after quite a while.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic