Q. Provide some background on Marina Sirtis, Counselor Troi on "Star Trek: The Next Generation." When she speaks, she seems to be trying to suppress some foreign accent, but we can't identify it. - A.F., Salt Lake City, Utah.
A. The accent's British. She was born and raised in London, studied at London's Guild Hall School of Music and Drama and made her professional debut playing Ophelia in "Hamlet" in a provincial repertory company. She did British TV before moving to the United States in 1986 and appeared in features "The Wicked Lady" and "Death Wish II."Q. On a recent episode of "Star Trek: The Next Generation," I was fascinated by Olivia D'Abo. What other work has she done? - J.T., Southgate, Mich.
A. D'Abo, 24, is best known as Karen Arnold, Kevin's older sister in "The Wonder Years." She's been acting since her teens and was in "Conan the Destroyer" at 15. She's done many TV guest roles and feature films ("Spirit of '76," "Beyond the Stars" and "Mission Kill"). Her cousin, Maryam D'Abo, was a Bond girl in "The Living Daylights."
Q. I'd appreciate anything you can tell me about Peter Gallagher, his movie or TV roles and his private life. - Mrs. J.T., Armada, Mich.
A. Gallagher, 37, was born in Ar-monk, N.Y. He attended Tufts University in Medford, Mass., and New England Conservatory and started out with the Boston Shakespeare Company. His Broadway debut was in "Grease" in 1978; his movie break was in "The Idol-maker" in 1980. He's done better on Broadway than movies or TV, with Tony nominations for "The Long Day's Journey Into Night" and "Guys and Dolls." His movies include "sex, lies and videotape" and "The Player." He's married to TV commercial producer Paula Har-wood.
Q. How old was Michelle Pfeiffer when she started acting? What school did she attend? - Y.H., Monroe, N.C.
A. Pfeiffer was a teenager when she started acting in high school drama class. That's all the schooling she had. What really launched her was winning the 1978 Miss Orange County Pageant. Pfeiffer's a native of Midway, Calif. She was signed by an agent and landed a small role on a "Fantasy Island" episode.
Q. Tell me the name of the musical in which Doris Day sang "Buttons and Bows." Is it on home video? - P.H., Salt Lake City.
A. It was Jane Russell who sang the 1948 Oscar winner "Buttons and Bows" in "The Paleface," co-starring Bob Hope. The movie is on tape and laser disc.
Q. What movie has the record for being shown the most on TV? My guess is "She Wore a Yellow Ribbon" or "Planet of the Apes." - R.P., Sacramento, Calif.
A. Good question, no real answer. But "Ribbon" and "Planet" probably wouldn't make the top 10. A few years ago, a limited survey turned up "Casablanca" as the most telecast movie. But that was before the annual Christmas onslaught of "It's a Wonderful Life" on cable and local stations. That's likely to change. Republic has reclaimed the rights to "Life" and intends to make stations pay to play it, as well as trying to retrieve and destroy copies that have been cut and colorized.
Q. My friend says James Earl Jones played Darth Vader in the "Star Wars" movies. I bitterly disagree. - P.S. Jr., Lackawana, N.Y.
A. This isn't simple. It was Jones' voice in all three of the "Star Wars" films, but British actor David Prowse was the man in the Darth Vader suit.
Q. Give me information on David Rasche, Jack in "Nurses." He looks familiar. What else has he starred in? - J.N., Phoenix.
A. Rasche made his biggest impression in the 1986-88 wacky cop comedy "Sledge Hammer!" He's been on "L.A. Law," "Kate and Al-lie," "Trials of Rosie O'Neill" and "Miami Vice." His comedy training came as a member of Chicago's Second City but he's also done serious drama on Broadway and in movies.
Q. I'm a die-hard fan of "Picket Fences." Tell me about Costas Mandylor, who plays hunky deputy Kenny Lacose. Where can I write? Incidentally, how's the show doing in the ratings? - T.A., Virginia Beach, Va.
A. Mandylor was born in Australia of Greek immigrant parents. He was a soccer player in Europe before deciding on acting and moving to Los Angeles in 1987. In 1988, he had his first major movie role in "Triumph of the Spirit." He's since been seen in "The Doors," "Soapdish" and "Mobsters." "Fences" is his first TV series. Write: 20th Century Fox Television, Box 900, Beverly Hills, CA 90213. Ratings were dismal but "Fences" made the cut. CBS has scheduled it for 10 p.m. ET Fridays in the fall.
Q. Last night I saw Anthony Andrews in "The Women He Loved" for the third time. He is an excellent actor. Why isn't he seen more often? What's his age? Is he married? - H.J.M., Phoenix City, Ala.
A. Andrews, 45, is married and the father of three. He works primarily in his native Britain but doesn't seem to push it, doing an occasional TV role.
Q. I saw Denise Nicholas, of "Room 222," on a cable program last week and was wondering if she is still acting. Where can I write to her? - P.D.W., Detroit, Mich.
A. Nicholas never stopped acting, although after "222" ended in 1974 and another series, "Baby, I'm Back," failed, her career lagged. She did a play and TV guest roles. In 1989, so the story goes, she heard "In the Heat of the Night" was looking for "a Denise Nicholas type" to play city councilwoman Harriet DeLong in the series. She got the job and has been in the series ever since, both as an actress and scriptwriter. Write: CBS-TV, 7800 Beverly Blvd., Los Angeles, CA 90036.
Q. Please identify the "Northern Exposure" actors and the role each one plays. - A.M.G., Akron, Ohio.
A. Rob Morrow is Joel Fleisch-man; Barry Corbin, Maurice Min-nifield; Janine Turner, Maggie O'Connell; John Collum, Holling Vincoeur; Darren E. Burrows, Ed Chigliak; John Corbett, Chris Stephens; Cynthia Geary, Shelly Tambo; Elaine Miles, Marilyn Whirlwind; Peg Phillips, Ruth-Anne.
Q. What happened to Paul Sor-vino on "Law and Order"? Why have there been three actors for one role? - Mrs. L.S.
A. Sorvino, who has dreamed of being an opera singer for years, decided to concentrate on that to protect his voice and to get off the mean streets of New York where "Law" is filmed. George Dzunda, who starred with Chris Noth in the series' first season, left to rejoin his family on the West Coast and because of behind-the-camera friction. Dzunda, Sorvino and now Jerry Orbach have played different detectives, not one role.
Q. We watched "Name That Tune." We're wondering who the emcee was. It was back in 1957 or 1958. - B.C., Vandalia, Fla.
A. "Tune" was around on various networks and in syndication from 1953 to 1959 and 1970 to 1980. The host you remember was George DeWitt, third of the six who did the show. The others: Red Benson, Bill Cullen, Richard Hayes, Dennis James, Tom Kennedy. The Kennedy version, seen in the 1970s, featured a vocalist named Kathie Lee Johnson. She's better known now as Kathie Lee Gifford.
Q. Dennis James has been doing a commercial. I remember him on TV years ago but can't remember the show. Can you help? - I.G.
A. It might be easier to name the shows James hasn't done. He's been at it since TV was a rarity in homes. He claims to be host of the first daytime game show, "Cash and Carry" in 1946, plus a batch of other TV firsts. The two shows with the longest runs that he's done were "Chance of a Lifetime," 1952-56, and "The New Price Is Right" (syndicated version), 1972-79.