I am truly afraid of ghosts after reading some things. How can I protect myself from them and will you tell me all you know about spirits and demons and poltergeists? I want to know what they can do to harm you and can they kill you or torture you Mentally/Psychically/Physically?

I can see that you are very worried about ghosts. I am sure that TV, movies and scary books have done a lot to spread the fear of angry, vengeful ghosts among most people. Holidays like Halloween and Day of the Dead etc are also opportunities to scare others or get scared. However, spirits are all non-violent by nature. In the Craft, we invite the Elements and other spirits to guide our intentions to fruition. The intention is to focus on the positive aspects of nature and use that to enable our spirit. Our own evil thoughts may create harmful energies that interfere with rituals and spells. As far as your question is concerned, you have no reason to fear spirits or demons or poltergeists. There are no spirits wandering around with the intention to hurt people. If you are really worried about this, it may be a good idea to do a protection spell. Cleanse yourself and your mind with a purifying herbal bath. Sit in front of the altar (or any quiet space) and close your eyes. Meditate on the blessings in your life. Think of all the people you cherish. Now imagine you and the people you love being enclosed in a purple shell of protection. The shell is around you and will deflect any evil or negative energy coming your way. Sit in that place of comfort for a while and visualize another shell around the first one. This will be your cocoon of protection. Whenever you have fearful thoughts, retreat into your shell of protection. This will help you avoid unwanted fear of spirits or anything else that visits your imagination. Hope this helps. Brightest Blessings.