Shortly after Langley Park School was shut down last June as part of the Prince George's County school-closing program, vandals defied the fresh "No Trespassing" signs at the door, broke every window, tore down walls and ceilings and destroyed the auditorium.

Langley Park and a dozen other public schools closed by the county and now standing vacant have become "virtual sitting ducks" for vandals, said Irv Smith, an assistant to County Executive Lawrence J. Hogan.

"It's sickening to go through that building," Smith said of Langley Park, which was slated to become a community recreation center but now, months later, is still littered with glass shards and debris.

"It's like someone set off a fragmentation bomb there," Smith said. "It looks like post-World War II Germany."

He said it may cost $100,000 to repair the brick building, "and who knows when we will be able to use it."

Plans to keep the 13 schools occupied by selling or leasing them have proved more difficult to implement than either county or school officials expected when the schools were ordered closed because of declining enrollments.

The plans have been stymied, officials said, because of a lack of interested buyers, rezoning problems and arguments with the state over who should pay more than $2 million in outstanding construction debts on the closed schools.

Last year, the state said it would stop making payments on school construction bonds if the schools were converted to private or noneducational use.

County officials say that decision meant they had to set extraordinarily high sales prices or rents to avoid losing money, and the price tags have driven off many interested parties, including some private schools.

Although the school board expected to save $100,000 a year on each school it closed, officials now say the county may lose considerably more than that when it eventually disposes of the properties.

The burden falls on the county government because after the school board decides to close a school and the state approves the decision the building is turned over to the county.

Increasingly anxious about the future of the empty schools and the cost of maintaining and guarding them, county officials sent out 1,000 letters last month to private developers and investors they thought could raise the money to buy the buildings and obtain the necessary exceptions from residential zoning to rehabilitate and occupy them.

The prospects included real estate brokers, physicians and lawyers, but so far the response has been minimal, the officials acknowledge.

"We want to return these buildings to the tax rolls as soon as possible," said Kenneth V. Duncan, the county administrative officer. "But we haven't been getting the response on them we'd hoped for."

The county has signed a contract to sell Somerset Elementary School in Bowie to a developer who plans to convert it into housing for the elderly.The building had been appraised at $900,000, but the selling price was only $500,000. That will pay off the construction debt and leave the county about $100,000.

Smith said the county has potential buyers for Berwyn Heights Elementary and Lakeland Special Center. Berwyn Heights is the cheapest school on the list, appraised at $61,000.

Officials said many of the school buildings could be used by county agencies, such as the Park and Planning Commission or the Police Department, but the agencies can not afford the high rents that would be required to pay the outstanding debts.

"We'd really like to get a public use (for the schools), but we may end up with no use for many of them," Smith said.

Smith said the county's problems also have led some officials to question the wisdom of the school board's decision.

"We assume the board of ed was correct in closing these schools," he said. "But who's to say in 5 or 10 years when the population changes again and these buildings have been torn down or sold whether that was the proper decision? It's a question that haunts everybody."