just because something cannot be explained immediately does not make it paranormal, wizardry or a parallel universe. just take a step back and think about what you are saying here... ghosts? we live on a tiny rock, spinning it's way through space around a huge ball of fire. life is just a chain of chemical reactions and tiny electric signals in patterns. there are no ghosts. when those signals cease to be, that is it. dead. done. why would a 'spirit' hang about?
as for Ouija Boards - well, they are just board games. there is nothing sinister about them. they do not contact the dead. the game was desinged for groups of friends to play. Parker games still holds the patent on it if i remember correctly. i think that says it all - it's just a board game. you can blame 'The Exorcist' for any link to ghosts. so a movie is dictating your feelings on a board game being attributed to the 'spirit' world.
fear ye not - you have no ghosts. the mind is a powerful thing. unlike spooky spectres!