Ghosts Real?

I was sitting on the computer, like now, and all of a sudden a something falls, ok it happens a lot. Than, my mom also tells me she hears things fall in the closet, im getting suspicous. Next, i hear people walkin in my house, very lightly but i hear it, it maybe the neihbors but still, i am scared. Next and last, i was playing a game on the computer, leave the house to visit grandparents and when my mom came home she told me that the admin acc was changed to normal, now i dont know if this is a bug or a ghost. Im not really a guy who believes in these kinds of things, but really, are their ghosts? If not, what could have caused these strange things? Thanks! im scared!