To be honest, I wouldn't use that oujii board again. I'm not a very religious person, though I believe in a higher power.
I was raised in an open home and one thing I learnt is that oujii boards can be BIG trouble.
My knowledge (which may be incorrect, but its MY beliefs) of the oujii board is that when you invoke the spirit, you may get more... agressive or troubling visitors.
My mother's experiences involved an entity who tried to mess with her and her friends (eg. telling them troubling news such as 'when they were going to die', or that one of them was going to die soon and that they'd been followed since birth by a dark power).
This story shows a pattern in experiences with the board.
My mother got rid of the entity by sitting in a circle with her friends, each using positive thoughts and energies to expel the guest who had outstayed their welcome.
You call your troubling visitor a demon and use a certain amount of faith to expel them.
That is perfectly acceptable, as what we believe in and put our faith into often manifests in reality.
If you wish to experience your previous problem again, fine go ahead, but I do not advice messing with the unknown.
I don't dictate other people, or tell them what to believe and what not, so you can either take my advice or trash it like a bad sandwich, I will not judge.