knock, knock...whos there?...(no answer)

ok so this happened to me a little over a year ago. iv tried to forget about it but i cant so maybe by telling people about this i will just feel a little better. and maybe someone can tell me something i dont already know.
about a year and a half ago i was at home with my sister. i was on my computer( the same one im using now ) and my sister was watching tv. i got off my computer and went upstairs to my room. to get to my room you have to pass the attick door wich actually faces my door to my room. so in order to get to my room you have to pass by the attick door. mys siters door is in the middle of my door and the attick so she too has to pass the attick door. now with that said. on the way to my roo, i had this sudden feel or pure terror( thats the only way i can describe it) iv actually felt this before but thats another story. i ran into my room and stayed there till the feeling passed. when it did i calmy and quickly walked downstairs and said nothing to my sister who was now on the computer. she didnt see me to notice something had happened. she eventually went upstairs exept she came running back down crying. when i asked her what i happened i was able to finish the sentance for her becaus ei know what had happened to her. she felt the same thing as me.
latter that night i finally went back upstairs to my room. this time i felt nothing as i walked by, just a little tingle in my stomach like something bad had happened but it was just a memory. well i was awken that night by a banging on that door. a violent banging that woke me up. but once awake it stopped. and i thought i had dreamed it. about 4 months passed and nothing happened. the i was once again sleeping and the banging started again. but this time my dog was on my bed with me, she could sleep through armagedon, yet when i looked up she was already standing on my bed looking at the door to the attick and would not leave my room. the banging also happened one more time while i was awake. so i know im not crazy. the dog herd it too.
iv tried to get some answers to what happened and i did. aparently the people we rent this house from are my mothers friends parents familly. and her friend lived here when he was younger. he told me the grandmother had died in the attick because back then it was her room.
so my question is why after all that time would she scare us and then not do anything ever again? any ideas im at a loss here. and need some sort of answer even if its just made up.

Try and get the grandma to talk to you.

I think what ilovepizza is trying to say, is that you should sit down, and try to have a seance. My question is, however, if that is your grandma, why would she convey a feeling of pure terror to you? I would expect that she would feel a little warmer, what with you being her grand(son?). Your house may be one of those that lie on a crossing of what are called 'laylines' (at least, I've heard them called that) laylines are currents of metaphysical energy, which is used by ghosts and spirits to make manifestations in the real world. However, when you get a crossing, they sort of cause a hole between the spiritual and human worlds, which allows less friendly spirits, and demons enter into your world. It seems from many accounts that I have read, that most houses still standing that are very old have histories. Perhaps yours is one of those houses. Most houses with histories are located in the vicinity of these laylines, according to some psychics. Well, I think that's all. Peace.

oooo wait a minute. im sorry if i didnt write clearly, the grandmother was my mothers friends grandmother. his familly rents this house to us. it was hid grandma. but the info you gave me was good enough for me. thanks.

That is very interesting. With almost all ghost stories I hear, the dog always goes bizerk. But you should definetly talk to the lady.

Something like that once happened to me. one night I had a dream that a demon was in my room, he kept throwing things at me and saying "You foolish Christian! You can't make it to heaven!" And since I can control my dreams, I tried to end it. It worked except that when I went to turn on my light, the bulb lit, but my room didn't. Then the demon reappeared and said the same stuff and kept throwing things at me, my door shut and I was trapped. The paradox happened atleast 15 times (me thinking I woke up, the light bulb, the demon, me trying to wake up, the light bulb, the demon etc.) finally I woke up, and my room was a mess, my room smelled bad and I my legs were tired like I had ran a long distance. Anyway, to make a long story short, I didn't go back into my room for a few days.