A FRIEND WHO is intelligent and sober tells me she won't be spending Halloween alone this year. No way.

She fears she may have ghosts, spirits, demons, whatever.

First the cigaretter lighter in her car suddenly popped out of the dash, casing and all, and fell to the floor. Then, while investigating strange noises in the basement of her town house in Potomac, Md., she found a box of art supplies vibrating in the corner.

Recently she was lunching at a restaurant in Alexandria when the bottom of the glass she was holding suddenly fell off, spilling ice tea all over.

She became somewhat agitated.

"I wanted to tell you," she said, "so in case anything strange happens to me you'll be sure to get to the bottom of it."

Not to worry, I said. Stay calm. And gave her a few reasonable explanations. It is easy to be skeptical in broad daylight.

But. . . Naw, couldn't be. Like the nights when you are alone and shadows on the edge of your vision appear mysteriously to move, and dreams that are only half-dreams because you are still awake shake you with imagined horrors.

"Mind's just playing tricks," you say. And pull the covers tight over your head.

But you wonder.

"I didn't believe in ghosts -- unitl today," was the way a Virginia reporter announced his conversion back. in 1962. He was covering a so-called potergeist incident at a local house His story, carried over news wires was reprinted in this newspaper.

"I went to a house. . . and got goosepimples dodging flying household objects that crashed to bits on the floor. . . A carpet rose eerily off the floor all by itself, vases jumped from mantlepieces and hurtled over people's heads and a mattress slid mysteriously off a bed and onto the floor. . . .

"[A] vase I had just examined on the living room mantlepiece hit the wall in the hallway at the front of the house. It apparently rounded a corner and crashed there under its own steam. There was no one in the living room."

The reporter was not alone. Witnesses to these strange movings about included William G. Roll, a parapsychologist from the Psychical Research Foundation in Durham, N.C., who says his group has studied several similar incidents. On some occasions, "we were satisfied that these phenomena could not be explained.

"There's never any doubt that these things happen," said Roll. "Because when an ashtray falls to the floor, you have to pick up the pieces. . . As far as I'm concerned, these things are real because I cannot dismiss what I see myself.

"You soon reach the point," said J.G. Pratt of the University of Virginia's parapsychology department, "that the evidence accumulates and reinforces itself. . . . I did myself witness three objects moving when there was nobody in a position to move them. In one case a book of matches and a tobacco pouch were flying across the room."

Some people believe in such things. Others don't. (But then Pascal once theorized that the earth, and therefore the universe, is nothing more than a molecule in something obviously much larger. Which might make us but a hair on a horse's. . . You get the picture.)

Those who do believe have long referred to this sort of manifestation as "poltergeist," or noisy ghost, phenomena. Parapsychologists, investigators of mind-over-matter occurrences, however, don't all believe in ghosts. If your saucers are flying, the cause is more likely to be you, not spirits from the beyond, some say.Some say children in their early teens, or epileptics, may be the likeliest to have encounters of the ghostly kind. They call this unwilled ability to make things shake, rattle and rock "recurrent spontaneous psychokinesis."

"Almost invariably," said Roll, "these things are connected with a member of the household. Somebody is always there when these things happen. It's our interpretation that there's a psychological or personal tension in the family or working place. And when this tension abates, the phenomena are likely to cease."

Roll described one incident at a novelty company warehouse in Florida in which a 19-year-old shipping clerk was the suspected source of poltergeist activity.

"It was quite a wonderful place for a poltergeist because there were so many nice things to break. Business practically came to a standstill while they were flying around. Finally, a medium was called in and this person performed various rites in the building [but] these were quite ineffective."

Usually it doesn't help much to move out if your dining room table decides to visit the lawn furniture of its own accord. The poltergeist, as it were, will follow you to the Holiday Inn or to Auntie Eustice's house. It's a case of the person, not the house, being haunted.

Some believers insist there is more to poltergeists than an overturned ego or scandal in the family. Welcome to the world of demons and spirits.

The Rev. Alphonsus Trabold, a professor of Theology at St. Bonaventure University in Olean, N.Y., is among the growing number of clergymen knowledgeable in parapsychology. He also believes in spirits, though he prefers to call them "psychic residue."

"The more classic cases," Trabold says, "are caused by some event that happened years ago. It may have been a murder. Or it may be someone who loved his house very much and some part of him remains. There are cases where departed members of a family have returned for some reason. But they don't usually last for a long time.

"Usually," Trabold said, "it's not a spirit as such but some psychic residue left behind."

Then there are the hard-core demonologists.

Ed and Lorraine Warren are a Connecticut husband and wife team who say they've been investigating psychic phenomena for 34 years. They are among those who dispute parapsychologists' theories that poltergeist occurences are a matter of the mind, or mind over matter.

In a 1974 case in Bridgeport, Conn., in which the Warrens were involved, local police officers said they saw furniture topple over, a refrigerator rise and move and a set of dishes fly across the room.

At a home in England from which Warren recently returned, the children, he said, have become nervous wrecks. Fires break out spontaneously, he says, the girls levitate mysteriously while bedroom furniture revolves around them. "One night, as they were lying in bed, cords from the curtains came off and wrapped themselves around on of the girls' neck and began to strangle her.

"I am fully aware that some people can, with their mind, move objects. I'm in agreement with the scientists in about three out of 10 cases. But I believe that sometimes we have something that is inhuman, that is demonic. We're not dealing with anything that scientists call a poltergeist case."

The Warrens say they "base much of our theory on our Christian upbringing." They will perform rites associated with exorcism to drive "demons" out of a house.They agree with Thabold, that exorcism, which is a ritual in some form in most major religions, should not be treated lightly.

"Throwing holy water around the room without knowing what he's doing is a horrible, dangerous thing for a clergyman to do," said Lorraine Warren. "He is dealing with something that has the wisdom and the cunning of the ages."

"I'm not really in favor of exorcism" said Thabold. "It can have a bad psychological effect on the mind. I'd rather try a positive approach, such as prayer or celebrating the eucharist. Sometimes you don't know what you're trying to drive out."

If you think you're being visited by the unknown, authorities agree that you should stay calm. Most "hauntings" don't last more than a few days or weeks. "Even if there is some energy there," said Thabold, "it can't really harm you."

Though troubled homeowners initially call the police, or a clergyman, when disturbances occur, many evenutually are referred to the Warrens or one of the country's psychical research organizations.

You can reach the Psychical Research Foundation, which receives about 12 poltergeist reports annually, by calling (919) 286-0714; the Warrens at (203) 268-8235.

Both will gladly look for your ghosts, no strings attached. CAPTION: Drawing, no caption, By Richard Decker; Copyright (c) 1957 The New Yorker Magazine, Inc.