What was going on when I was born?

The booming use of personal computers is enabling thousands of small enterprises - lumber yards and law offices, small banks, shops and farms - to do a better job of running their businesses. With a speed and precision that was once enjoyed only by the nation's largest companies, they can now figure finances, control inventories and compute costs - in short, get a better grip on their own business destiny. ''There is nothing the computer does that we couldn't do before,'' said Albert P. Oliveira, who uses it to track a score of salespeople for the Equipment Sales Company here in Lowell. ''But it is so incredibly fast, and easy, that we can do far more.'' Driving this headlong overhaul of business practices are not the small computers themselves, but the remarkably popular genre of personal computer programs known as electronic spreadsheets.

The Central Elections Council today declared Jose Napoleon Duarte, the moderate candidate, the winner of Sunday's presidential election. He received almost 54 percent of the vote. The far-right opposition party said it would not accept the council's tally. ''The elections don't have any credibility and the results are a farce,'' said Hugo Barrera, the vice presidential candidate for the right-wing Nationalist Republican Alliance, known as Arena. ''In no way will we accept the victory of Duarte.''

Irony, inevitability and miscalculation marked the Chancellor's precipitous downfall. Page 14. Anthony John Alvarado resigned yesterday as Chancellor of the New York City school system, four days before he was to face a disciplinary hearing on charges of professional misconduct. His resignation was offered with a ''sincere and profound apology to the city I love and its citizens, whom I deeply respect.''

Sales at the retail level surged 2.9 percent last month, the Commerce Department reported today. The Administration hailed the report, but economists said that it could mean fresh increases in interest rates soon. They noted that much of the sales growth had occurred in so-called big-ticket items - cars and appliances, for example - that are generally bought on credit. This exacerbates the competition for financing.

Eight people were killed and seven others were injured last night in a fire at a haunted house attraction at an amusement park in Jackson, N.J., according to authorities. The identities and ages of the dead were not immediately known. The victims were believed to be teen-age visitors at the park - Six Flags Great Adventure - according to the Jackson Police Commissioner, Richard Borys. He said that as of midnight the bodies still had not been removed from the rubble of the building, which was destroyed.

On the surface, the House debate that led to approval of President Reagan's aid package for El Salvador was over a defined and practical issue: Should Congress tie the aid to performance on human rights by the Salvadoran Government, and if so, how? Or should the President be given the flexibility to do it his way? It was not over whether Washington should provide military aid or whether Communism should be stopped. Virtually all the House debaters agreed on that. But as the legislators pored through the practical matter of whether to make the aid conditional or unconditional, it became clear that the debate was about something much deeper. It was about the nature of change in the third world and the fundamental direction of United States foreign policy in dealing with it.

The Government has begun its biggest crackdown against Colombia's multi- billion dollar narcotics industry. The action follows the murder two weeks ago of the country's Justice Minister, who the Government says was killed by men working for cocaine dealers. Since the killing, more than 100 suspects have been arrested, including four well-known traffickers. Dozens of raids have been carried out against homes and farms thought to be used by drug traders and several properties acquired with cocaine profits have been seized by the authorities.

Corsican separatists demanding political status for nationalist prisoners detonated six bombs early today at banks and public buildings, causing damage but no injuries, the police said. The bombs went off in succession at about 1 A.M. in this southern port city. The Corsican National Liberation Front took responsibility for the attacks.

Poor Pique. The official mascot for the 1986 World Cup soccer tournament in Mexico is less than a month old, but he is already a target for Mexican nationalists and the butt of tasteless jokes. The cartoon character was chosen for his commercial potential, not because he was a political or humorous symbol. But his pointed, green jalapeno pepper head, which sticks up through a large yellow sombero, and his black handlebar mustache, red nose and oversized soccer shoes recall an image of Mexico that many people here say they would prefer to forget.

With a Government escort standing by, foreign journalists on a tour of a rebel area have heard charges from residents that soldiers pressing a counterinsurgency drive have resorted to raping, torturing, beating and murdering villagers. These statements by villagers and others, some given in the open, others privately, came during a two-day Government-conducted visit to Matabeleland, an area where many followers of the opposition leader Joshua Nkomo live. As the tour ended Thursday night, a Government spokesman said it had proved that allegations published abroad of ''brutality on a massive scale have been false.''

The insurgents who oppose South Africa's disputed control of South-West Africa and their white South African adversaries and other political foes met here today in a major effort to seek a settlement, but a procedural wrangle held up substantive deliberations for hours. Delegates from the insurgent group said the complication, which stretched into the night, partly offset what optimism preceded the talks and reinforced insurgent skepticism about the outcome. The negotiations are being held under the auspices of President Kenneth D. Kaunda of Zambia. South Africa, which governs South-West Africa, or Namibia, under an expired mandate from the League of Nations, is represented by its administrator general - a kind of viceroy - in the territory. The administrator general, Dr. Willie van Niekerk, is co-chairman of the talks with President Kaunda. The other delegations are the South- West Africa People's Organization, a Soviet-armed insurgent group that has been fighting a low-key bush war for more than 17 years, and what is called the Multiparty Conference, an amalgamation of six internal parties seen by the insurgents as fronts for South Africa.

Plainclothes policemen have posted a 24-hour guard at the apartment of a woman who briefly visited Andrei D. Sakharov and his wife in Gorky last week and reported on their plight. The woman, Irina G. Kristi, a 46- year-old mathematician, said on her return last Tuesday that Dr. Sakharov, the physicist and dissident, had begun a hunger strike May 2 to back demands for medical treatment abroad for his wife, Yelena G. Bonner.