What was going on when I was born?

Maybe it is time to take Vitas Gerulaitis seriously again on the tennis tour. After sliding from fourth to ninth in the world rankings and admittedly on holiday for the second half of the 1980 season, Gerulaitis collected the $175,000 first prize in the Molson Challenge today with a 6-4, 4-6, 6-3, 6-3 victory over John McEnroe. Bjorn Borg defaulted the third-place playoff to Jimmy Connors with what officials described as a ''touch of the flu.'' The difference between third-and fourth-place money in the eight-player event was $30,000 ($80,000 to $50,000), but Borg might have received as much as a $100,000 guarantee and probably did not want to play a meaningless match against a rival he had already lost to once here.

Since Michael Ray Richardson led a third-quarter surge that carried the Knicks to a 116-102 victory over the Nets today, he was asked if he felt any sympathy for a team that was struggling with a 15-44 record. ''In this league you don't feel sorry for anyone,'' he said. Richardson, the Knick playmaker, scored 14 of his 20 points in the third period. His scoring came mostly on the fast break as the Knicks built a 25-point advantage and coasted to their fifth straight victory and second over the Nets in two days. The Nets have lost five games in a row.

Semiconductor makers are bracing for a poor year. Mounting competition from Japan is combining with soft demand and lower prices to worsen the downturn in earnings that began in the fourth quarter of 1980. Semiconductor sales rose 26 percent last year, compared with 36 percent in 1979. (Page D1.)

For six years Edward M. Korry, United States Ambassador to Chile from 1967 to 1971, has insisted that he was not involved in and indeed tried to stop White House efforts to induce a military coup in Chile in 1970 to prevent Dr. Salvador Allende Gossens, a Marxist, from assuming the presidency. Evidence has come to light suggesting that Mr. Korry, despite his strong opposition to the Allende candidacy, was frozen out of the planning for a proposed military coup and warned the White House that it would be risking another ''Bay of Pigs'' if it got involved in military plots to stop Dr. Allende's election. Mr. Korry has not worked in his professions, journalism or public affairs, since 1974, two years after the columnist Jack Anderson published International Telephone and Telegraph Corporation documents that seemingly linked Mr. Korry to joint I.T.T.-Central Intelligence Agency operations to block Dr. Allende's election. Mr. Korry expressed particular bitterness toward The New York Times for what he said was unfair reporting about his role in articles in 1974 that revealed the C.I.A.'s activities in Chile and in refusing in later years, despite his entreaties, to investigate his actions accurately.

With unemployment mounting sharply, Spanish labor has demonstrated new signs of pragmatism and moderation, dealing a recent rebuff to the Communist-dominated Workers' Commissions in plant elections and giving important victories to the Socialists' General Workers' Union. The striking progress registered by the Socialist union, which pulled to nearly equal strength with the Workers' Commissions in balloting that began in October, was also an unspoken victory for Spain's new business executive's organization. Under the deft guidance of Carlos Ferrer Salat, a Catalan electronics executive and a one-time Davis Cup tennis star, the Spanish Business Confederation has achieved a major goal: clipping the Communists' wings. Ministry of Labor figures show that 30.7 percent of the 158,454 factory delegates elected over the past four months were from the Workers' Commissions, 29.6 percent from the General Workers' Union and 9.4 percent from the Workers' Union, a Government-backed group. Compared with the last balloting in 1978, the vote means a drop of almost 4 percent for the Communist-led group, and an impressive 8 percent jump for the Socialists.

Clusters of huge wholesale warehouses that have sprung up since the mid-1970's in the Hackensack Meadowlands have become the targets of burglaries running into millions of dollars. In the most recent large break-in, thieves made off last weekend with $1.5 million in jade statuary and gold jewelry imported from China. That theft - from a $6 million collection that is currently the subject of a court fight in Hackensack - follows hundreds of burglaries of wholesale merchandise from such warehouses in recent years. In the burglaries, bands of skilled thieves who bypassed alarm systems have pounded holes in warehouse walls and roofs and have trucked away goods that had a total potential retail value of millions of dollars, the Carlstadt police say.

At the Greenwich Country Club, lunch is being served on paper plates, and the martinis come in plastic cups. In one apartment complex downtown, a resident called the police the other day to report that a neighbor was drawing a bath. Even the Town Hall bathrooms sport signs imploring, ''Don't Be a Flusher.'' With water supplies even lower than in other communities around New York City, a kind of nervous jocularity can be found in Greenwich these days. Residents joke about their predicament (''We've been cold all winter - now we're cold and dirty''). They discuss their new toilet habits with the earthiness of soldiers and espouse water conservation with gusto and civic pride. But they are also afraid. ''It's frightening, really, to think you might go home one day and turn on the tap and there'll be nothing there,'' said Joan Kaiser, a secretary. ''You just have to prepare for the doomsday type of condition.''

United States semiconductor manufacturers, faced with falling prices, softening demand and mounting competition from the Japanese, are girding for a year of depressed profits and tough management decisions. The downturn, already reflected in earnings for the fourth quarter of 1980, follows four years of robust growth. Industrywide figures show that semiconductor sales jumped 36 percent in 1979 and that the market remained strong far enough into 1980 to result in a 26 percent sales increase for the year. The fourth-quarter decline was most apparent at the Intel Corporation and Advanced Micro Devices, both major producers of semiconductors. Intel reported that its earnings were down 4 percent from the fourth quarter of 1979, while Advanced Micro Devices reported a 9 percent drop.

In a warren of windowless rooms in the New Executive Office Building, a block from the White House, a team of economists from southern California has been drafting ''scenarios'' that show President Reagan's economic policies bringing about a dramatic slowing of inflation. One such projection shows the nation's inflation rate dropping from more than 10 percent now to roughly 6.5 percent in 1982 and even lower, to possibly less than 5 percent, by the 1984 elections. This is a faster improvement than most economists believe possible. The conventional view is that a policy of economic restraint might slow inflation by roughly one percentage point a year.

''Sex has been a good business for me,'' says Duane Colglazier, president of Pleasure Chest Ltd., which he describes as the nation's largest seller of sexual paraphernalia. A former Wall Street trader who opened his sex business in 1971, Mr. Colglazier has found success in what now often seems the obsolete manner of the mythic American entrepreneur: He worked long hours, generally employed his own capital or returned company profits to his business and paid close attention to detail. Today he has nine retail stores across the country, including one in Greenwich Village, and, he says, sales that approach $10 million a year. Mr. Colglazier believes himself a pioneer in an industry with significant growth potential. Sitting in his company's headquarters on the sixth floor of an office and warehouse building on West 20th Street in Manhattan, he talks disapprovingly of traditional sex emporiums, like those in the Times Square area. He regards those facilities, which feature such attractions as film clips of sex acts, displays of sexual devices -much like those Mr. Colglazier sells - and shelves of sex magazines and books as essentially obsolete businesses that have, by failing to modernize their display and marketing techniques, not kept pace with the times. ''I sometimes feel embarrassed by them,'' he said.

International Poland's leading opposition group will be investigated, the Government said. The official announcement of an ''inquiry'' into the Committee for Social Self-Defense, an ally of the independent labor union Solidarity, appeared to indicate a crackdown. Meanwhile, talks between Solidarity leaders and a Government delegation aimed at averting a general strike today in the southwestern town of Jelenia Gora were recessed at the delegation's request. It said it wished to consult authorities in Warsaw. (Page A1, Column 6.) Custody of Cynthia B. Dwyer will be given by Iran to the Swiss Embassy in Teheran, and she might leave Iran today, the State Department reported. Mrs. Dwyer was found guilty of espionage by an Iranian revolutionary court yesterday and ordered to leave the country. According to her family in Amherst, N.Y., near Buffalo, Mrs. Dwyer went to Iran as a free-lance journalist last April to write about the revolution. (A1:5.)

ON the 19th floor of the Summit Hotel, high over Lexington Avenue, the odd couple was stirring early: Dave Winfield, 29 years old, 6 feet 6 inches tall, crisp and cool; his agent, Albert S. Frohman, 54 years old, 5 feet 4 inches short, rumpled and emotional. ''Opposites attract,'' said Frohman, who retired as a kosher caterer in New York five years ago and moved to California. ''People wouldn't understand if they saw the difference in age, race, religion. If people had that relationship, father and son, they'd be better off.'' He paused, and added one of his postscripts: ''We're not looking to play on harp strings.'' ''How many people would you trust your life with?'' Winfield asked. ''Protect your back?'' ''No contract, no nothing,'' Frohman said, explaining the relationship in another way. ''David is the executor of my estate. That's the only piece of paper between us.''