According to some (proven) theories and beliefs, after the death of the physical body, the ethereal/astral body still stays around the physical body and here on Earth for 40 days more, passing through each element (Earth, Air, Water, Fire) struggling to adjust itself to the new situation, that is its own death, and freeing itself from all the strings it has been attached to during its earthly life. While some people are fully prepared for this crossing (I know some of my family members were), there are others who always believed that with the death of the physical body, their very existence ends as well. They are having much trouble accepting their new environment after the death that they keep resisting/refusing to continue with their destined way...
It is recommended to use, if one wants, the Ouija board to contact the deceased person while his/her soul is still on Earth. After the period of the 40 days, he/she moves on, and it is dangerous to contact her/him because you would not contact him/her, but some other entity with enough intelligence to mimic him/her, or at the very least some other entity who just wants to enter our world or have some fun with us.
My grandfather died in April of 2012. During the 40 days after his death, we all could still sense his presence. His favourite drink was brandy, and we left a full bottle of it on the window sill near the dead body. After an hour from that moment, the entire bottle was empty and the bottle was closed. We were in the same room, there was only a curtain separating the body and four of us who were preparing the body for burial.