May 19, 1987

LEAD: A new breed of vandals, working within a vast network of computer ''bulletin boards,'' are devising sophisticated software programs that erase and scramble the computer files of unsuspecting users.

LEAD: The Internal Revenue Service today introduced the main income tax forms that will be used under the Tax Reform Act of 1986, giving individuals a preview of the added complications they will have to deal with next year under the sweeping new law.

LEAD: Robert Maxwell, the British publisher who says he intends to head one of the world's biggest communications companies by 1990, took a step in that direction yesterday by offering $1.7 billion for Harcourt Brace Jovanovich Inc., one of the world's biggest educational publishers.

LEAD: Archeologists and historians are finally on the tracks of the first large party of Europeans to plunge deep into the interior of what is now the United States.

LEAD: The Federal Government has temporarily suspended its deadline on bidding for a $4.5 billion contract to modernize its telephone system, following complaints by the American Telephone and Telegraph Company over bidding procedures.

LEAD: In a significant expansion of Federal civil rights protections, the Supreme Court ruled unanimously today that Arabs, Jews and members of other ethnic groups may sue under a post-Civil War law's broad prohibition against discrimination.

LEAD: Though the nighttime temperature may still hover near freezing in this central Adirondack town, summer can be heard approaching from the precincts of the school parking lot. It is a distinctive sound, as if a swarm of patriotic hornets were being pursued by an offbeat, determined percussionist.

LEAD: In France, Jacques Stern is admired as a corporate savior for rescuing Groupe Bull, the country's largest computer company, from the brink of bankruptcy. While that was quite a feat, many in the computer industry say that he faces a far tougher task in trying to resurrect Honeywell Bull Inc.

LEAD: After Jayne Kraman's third child, Max, came along two years ago she was desperate for a mother's helper, so she hired a live-in au pair from West Germany. The young woman came on a tourist visa, meaning it was illegal for her to work here, but not for Mrs. Kraman, a freelance writer who lives in Brooklyn, to employ her.

LEAD: With a Bible open before him, the Rev. Daniel Mercaldo spoke derisively of the equal rights amendment, abortion, the teaching of evolution and working women.

LEAD: A BIZARRE form of matter distinct from the solids, liquids and gases that make up the everyday world may soon lead to radical improvements in products as varied as plastics and potato chips, scientists predict.

LEAD: A senior aide to Governor Cuomo, modifying earlier administration statements on prison overcrowding, said today that it was unlikely the state would attempt to take control of two 700-bed prisons that it currently plans to build for New York City.