Everyone in China who has been to high school has such a file. The files are irreplaceable histories of achievement and failure, the starting point for potential employers, government officials and others judging an individual’s worth. Often keys to the future, they are locked tight in government, school or workplace cabinets to eliminate any chance they might vanish.

But two years ago, Mr. Xue’s file did vanish. So did the files of at least 10 others, all 2006 college graduates with exemplary records, all from poor families living near this gritty north-central town on the wide banks of the Yellow River.

With the Manila folders went their futures, they say.

Local officials said the files were lost when state workers moved them from the first to the second floor of a government building. But the graduates say they believe officials stole the files and sold them to underachievers seeking new identities and better job prospects — a claim bolstered by a string of similar cases across China.

Today, Mr. Xue, who had hoped to work at a state-owned oil company, sells real estate door to door, a step up from past jobs passing out leaflets and serving drinks at an Internet cafe. Wang Yong, who aspired to be a teacher or a bank officer, works odd jobs. Wang Jindong, who had a shot at a job at a state chemical firm, is a construction day laborer, earning less than $10 a day.

“If you don’t have it, just forget it!” Wang Jindong, now 27, said of his file. “No matter how capable you are, they will not hire you. Their first reaction is that you are a crook.”

Perhaps no group here is more vilified and mistrusted than China’s local officials, who shoulder much of the blame for corruption within the Communist Party. The party constantly vows to rein them in; in October, President Hu Jintao said a clean party was “a matter of life and death.”

Critics contend that China’s one-party system breeds graft that only democratic reforms can check. But China’s leaders say the solution is not grass-roots checks on power, but smarter oversight and crime-fighting.

Public policy specialists say China is shifting its emphasis from headline-grabbing corruption cases to more systematic ways to hold officials accountable. The government opened an anticorruption hot line last month to encourage whistle-blowers. A few localities require that officials disclose their family assets to the party.

But in Wubu, a struggling town of 80,000 banked by steep hills and coal mines, citizens say that local officials answer to no one, and that anyone who dares challenge them is punished.

“When the central government talks about the economy and development, it sounds so great,” said Mr. Wang, the day laborer. “But at the local level, corrupt officials make all their money off of local people.”

Student files are a proven moneymaker for corrupt state workers. Four years ago, teachers in Jilin Province were caught selling two students’ files for $2,500 and $3,600; the police suspected that they intended to sell a dozen more. In May, the former head of a township government in Hunan Province admitted that he had paid more than $7,000 to steal the identity of a classmate of his daughter, so his daughter could attend college using the classmate’s records.

While not quite as important as in Communist China’s early days, when it was a powerful tool of social control, the file, called a dangan, is an absolute requirement for state employment and a means to bolster a candidate’s chances for some private-sector jobs, labor experts say. Because documents are collected over several years and signed by many people, they are virtually impossible to replicate.

So in September 2007, when one Wubu graduate sought work at a local bank and discovered that his file was gone, word spread fast. For the next two years, his parents and a group of other parents in similar straits said, they sought help at every level of the bureaucracy.

The government’s answer, they said, was to reject any inquiry, place the graduates’ parents under police surveillance and repeatedly detain them. Last February, they said, five parents trying to petition the national government were locked in an unofficial jail in Beijing for nine days.

“We are so exhausted,” said one tearful mother, Song Heping. “Our nerves are about to snap from this torture. The officials who were responsible not only have not been punished, they have been promoted.”

Wubu officials did not respond to repeated inquiries. One Chinese television journalist said they told him they had resolved the matter simply by creating new folders. But families say the folders held nothing but brief, error-riddled résumés that employers reflexively reject as fake.

The parents are uniformly poor: one father drives a three-wheel taxi, earning just 15 cents per passenger.

Mr. Xue’s parents sacrificed even more than most, in the belief that education would lead their children out of poverty. They earn just $450 a year growing dates, and live near a dirt mountain path, drinking well water and cooking over a wood fire.

Mr Xue, the oldest child, wore secondhand clothes and skipped meals throughout high school. When he won admission to a university in Xian, 400 miles away, his parents borrowed to cover the $1,500 in annual expenses. Initially, it seemed the bet would pay off: he said he had had a chance to work at an oil company with a monthly salary of $735.

But the job evaporated with his dangan. “It was a catastrophe,” he said. Now he earns a base salary of $90 a month as a door-to-door salesman and lives in a tiny, dingy room in a Xian slum.

The woman he hoped to marry left him because her parents said he would never have a stable job. His mother suffered a nervous breakdown, and the family debt ballooned. his father, Xue Ruzhan, said he owed more than $10,000 — more than twice what his property is worth.

“What is the point of continuing to live?” the father said. “Sometimes I want to commit suicide. These corrupt officials destroyed all our hopes.”

Including, it seems, the hopes of Longlong’s younger sister, Xiaomei, an 11th grader who once thought she would follow him to a university degree.

No more. “I want to quit,” she said during a school lunch break. “My brother graduated from college. What good did it do him?”