Can I summon a demon I have seen before?

When I was younger maybe 10 before I knew what ghosts were I was lay in bed one night and I woke up to see a dark figure totally black although it had light shining in from new door Which was very faint it still would of shown a normal person standing there up he had the outline of what he looked like he was wearing which was a top hat a walking cane and a long cloak and he had medium lenth curly hair I knew it wasn't one of my parents as I cOuld see into both of there rooms which were opposite and the doors were closed this ghost / spirit / demon had his face turned facing me I stared thinking it was a dream but after a bit I knew it wasn't it was real I hid under my covers then ten seconds later I lifted my head from them and he was gone , he must of gone down my stairs as he was stood on top of them he was about 10 ft away from me , I'm not sure if I did this before or after I saw the spirit but I tried to contact the dead just with a candle and a Mirror as I didn't really know what I was doing but if I did it before would that of had an effect? How do I summon this spirit again? I need to know why they came to me , I don't know the exact date he came to me but is there anything I can't say/chant to bring this spirit back? And also I've been seeing little balls of light if I turn my head it will hover still for about a second then move away and this has happened in the dark and day can anyone explain or help with these problems? Many thanks for any helping comments:)

simple answer yes. in order to see this spirit again find 5 hits of good acid and focus. demons aren't real. as Neitzche said there is insufficient love in the world to give any to an imaginary being. try to find something real instead of chasing shadows.

What you saw was not a demon. Demons give off an evil vibe, that makes you shake in utter terror. You clearly were not that terrified. I'm going to guess it was a ghost, because of it's appearance and what you've said of it. A demon would be evil, and would not look human.
There is really nothing to do to bring it back, and even if there was, that would not be a wise idea. You'd just be putting yourself in danger. Trust me on that.
Hope this helped. Good luck.

You can try, but demons aren't real.  What is real, however, is power of suggestion. If you think you summoned an invisible boogeyman, your mind will come up with all sorts of ways to interpret everything around you as evidence of the presence of this invisible being.

It sounds like you are remembering a dream.  It can be very difficult when remembering what happened a long time ago if you are remembering a vivid dream or something that was real.