The Justice Department said it won't appeal the sentence of Robert T. Morris Jr., who was placed on three years' probation, fined and ordered to perform community service for paralyzing a nationwide computer network.

Affiliated Publications, parent of the Boston Globe, agreed to acquire 80 percent of the outstanding stock of ASM Communications, publisher of Adweek, Marketing Week and Photo District News. Terms were not disclosed.

ConAgra will help manage some poultry and hog operations in the Soviet Union under a new agreement. Terms were not disclosed.

Marriott said it will open a day-care center in its Bethesda headquarters this fall that will accommodate 63 children of area employees. The center will be developed and operated for Marriott by Corporate Child Care.

ERC Environmental and Energy Services of Fairfax plans to discontinue its digital conversion division in its Roanoke facility. The division converts engineering drawings into digital formats for use in computer-aided design systems.

Carolco Pictures, known for producing the "Rambo" series and other action films, said it plans to sell a 10 percent stake to Pioneer LDCA, a unit of Japan's Pioneer Electronic Corp.

Japan's trade surplus took its sharpest fall in April since June 1979, the government reported. The Finance Ministry said in a preliminary report that the current account surplus plunged 75.5 percent from the March level and was down 69.6 percent from a year earlier.

Mortgage rates were mixed this week. Fixed-rate mortgages averaged 10.29 percent, down from 10.33 percent last week, while one-year adjustable-rate mortgages had an average initial rate of 8.55 percent, up from 8.53 percent last week, the Federal Home Loan Mortgage Corp. said.

The Florida Supreme Court abolished a sales tax exemption after ruling that the tax was unconstitutionally levied on magazines and not on newspapers. The ruling came in response to an effort by magazine publishers to obtain the exemption.

IBM received a contract from the Soviet Union to supply more than 13,000 personal computers for use in schools. Value of the deal was not disclosed.

Argentina is ready after a two-year lapse to resume interest payments on its $60 billion foreign debt, but creditor banks apparently want more than the government is offering, according to a newspaper report.

BankAmerica bought the branches and most of the healthy assets of Phoenix-based Western Savings & Loan, Arizona's second-largest thrift, for $81 million. The sale was arranged by the federal agency created to dispose of the assets of ailing thrifts, and is expected to eventually cost the government about $1.7 billion because it is retaining Western's problem assets.