Okay kiddo, so when you watch a movie or play a video game, sometimes there are characters who die or things that go wrong. And sometimes, the people who made the movie or game need to fix those things so the story can keep going.
So they might show the same story again, but this time, they change things around to fix the problems. That's called a reboot.
Think of it like this: when you were little, you might have drawn a picture that didn't look quite right. Maybe a line was crooked or you colored outside the lines. But instead of getting rid of the whole picture, you would start over and try to make it better. That's what a reboot is for movies and games.
Does that make more sense hoonie?