My haunting started when I was around 17 in my mum's house in Scotland. At first, I thought it was my imagination. Photos would be moved around in my bedroom and I'd find doors and windows open when I was sure I'd closed them. Things gradually got more pronounced - the TV and lights started to switch themselves on. I saw a shadowy figure standing at the top of the staircase, but dismissed it as my imagination. The family dog refused to come into my bedroom and no amount of coaxing with food would get her to go in there. My sister (who had the bedroom next door) told me that she could hear banging and whispering coming from my room at night when I was asleep. Our mum dismissed us both as being crazy. The activity seemed to slowly spread to other areas of the house. An entire set of pans went missing from the kitchen (my mum and sister turned the place upside down looking for them), then reappeared, and plates flew off of the kitchen table and smashed against the wall. My brother and sister started to hear "evil" sounding whispering in their bedrooms, but couldn't understand what was being said. Things came to a head when my sister's bedroom door started banging and shaking while closed as if it was being kicked. My mum and sister were both in the room at the time and both witnessed it. My mum called a priest, who came and blessed the house. Everything went back to normal.
We put it behind us until about 18 months later. I was 20 by now and lived in a new apartment with my boyfriend. My sister and I were out shopping and were checking out the make-up aisle of a local pharmacy, when I heard a man whisper my name. When I turned around, the only person there was my sister. She said that my name had been said twice. The first time was too quiet and I didn't hear it, the second time was louder and I turned around. The only other person in the shop was a female cashier. My sister said that the voice came from directly behind her and that she felt breath on her neck. I am not sure what triggered this, but it started a whole lot of activity in my new apartment. I constantly had a creepy feeling that I was being watched and was afraid to be in the apartment on my own. My dogs (I had 2) would growl at nothing and move their heads as if they were watching something cross the room. I would close and lock windows only to wake up in the middle of the night with them wide open. Lights and the TV would come on after I'd switched them off. The house was always freezing cold no matter how high we turned the heating. Sometimes, I could feel something sitting on my bed or touching me. It will sound stupid, but I was always afraid of putting my hands or feet outside of the bedcovers at night because I was scared that something would happen if I did. I was scared to look in the mirror because of the over-riding feeling that I'd see something behind me if I did.
I don't know anyone who has passed away and have no idea who the spirit is. It felt evil and was really frightening. I used a home-made ouija board (made from paper) at my mum's house once with some friends when I was about 14, but it didn't work. To my knowledge, none of the friends have experienced any problems. Does anyone have any idea what this could be? I am not religious, so please no religious messages.
Anyway, you said you saw your sister and she smiled in a really creepy way. Would your REAL sister normally do that. If not I would have to go with the demon theory.